Physical evidence is any tangible article, small or large, that tends to prove or disprove a point in question. It may be used to

1. Reconstruct the crime

2. Identify the participants

3. Confirm or discredit an alibi

The proper collection and disposition of physical or trace evidence from the crime scene and the body of the deceased is of utmost importance to the investigation and eventual court presentation. The evidence must have been obtained legally in order for it to be admissible. Therefore, it is imperative that the legal authority to collect the evidence and the proper collection techniques be considered prior to the actual collection of the evidence.*

Procedures for Collection of Evidence

In order to be introduced as physical evidence in a trial, an article must

Be properly identified

Show a proper chain of custody

Be material and relevant

Meet all legal requirements

The crime scene technician or crime scene investigator who is summoned to the scene should have operational supervision over gathering, collection, and marking of evidence for identification. However, the investigator assigned to the case is

* The techniques of collection presented in this chapter are based on the recommendations and procedures of Dr. Robert C. Shaler. Dr. Shaler, who holds an M.S. and Ph.D. in biochemistry from Pennsylvania State University, is the director of serology for the New York City Medical Examiner's Office. He has lectured at various universities and forensic symposia and has published several articles related to the forensic sciences.

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still in charge of the investigation and should be consulted prior to any evidence gathering or crime scene processing.

The proper collection and disposition of evidence will be accomplished if the following guidelines are adhered to:

1. Each piece of evidence should be marked (on the container or item as applicable) to show its original position and location. This information should also be recorded in the investigator's notebook.

2. Each article should be marked distinctively by the searching officer to identify the person who found the particular piece of evidence. In cases of small or fluid specimens, this marking is done on the container.

3. Each item should be described exactly and completely with the corresponding case numbers affixed and the date and time of collection indicated.

4. Each item should be packaged in a separate, clean, and properly sized container to prevent cross-contamination or damage.

5. Each package should be sealed to retain evidence and prevent any unauthorized handling.

6. Each piece of evidence should show proper disposition:

a. Police department laboratory

b. Property clerk's office

c. FBI laboratory

7. Proper records should be kept regarding each piece of evidence showing chain of custody. These records should reflect any movement of the evidence from the point of origin to its final disposition.

Remember: Each item should be photographed before it is collected as evidence. These photographs should include a long-range view to show the relationship of the object to its surroundings and a close-range view to show the actual item being collected. (See Chapter 6, "The Crime Scene Photographs.")

General Types of Evidence

Physical evidence

Testimonial evidence

Documentary evidence

Behavioral evidence

In practical homicide investigation, each of these general types of evidence becomes crucial in the identification, apprehension, and subsequent prosecution of offenders. However, the investigator should appreciate the nature of physical evidence.

Classifications of Physical Evidence

Class Evidence

Class evidence is that which cannot be forensically identified with a specific source to the exclusion of all others. Examples are the non-DNA analysis of

Blood Soil

Semen Glass (see Glass as possible individualistic evidence

Saliva later in this chapter)

Hair Wood

Fibers Plant materials

Animal materials

Individualistic Evidence

Individualistic evidence is evidence that can be positively and forensically identified with a specific source to the exclusion of all other sources. Examples are

DNA analysis of body fluids and hair

Latent prints

Fracture matches

Bite marks

Specific handwriting

Collection of Specific Types of Evidence

The homicide investigator is usually confronted with the same general type of evidence in most murder investigations, such as blood, bullets, and fingerprints. The evidence ordinarily falls within three distinct categories: body materials, objects, and impressions.

This text will focus on the practical methods for collection of types of evidence commonly found at the scene of a homicide. The more advanced and detailed methodologies have been purposefully omitted from this section because they are usually beyond the capability of the average investigator and are best performed by crime scene technicians and other experts who have been specially trained in forensic science techniques.*

* These advanced methodologies are covered in several comprehensive works on the subject. If you wish for a more in-depth knowledge of evidence collection, consult the more technical textbooks on forensic science. See, for example, Lee, H., T. Palmbach, and M. Miller, Henry Lee's Crime Scene Handbook, San Diego, California: Academic Press, 2001; Kirk, P., Crime Investigation, 2nd ed., New York: John Wiley & Sons, Inc., 1974; Lee, H., Crime Scene Investigation, Taiwan, Republic of China: Central Police University Press, 1994; and Saferstein, R., Criminalistics: An Introduction to Forensic Science, 6th ed., Englewood Cliffs, New Jersey: Prentice Hall.

Body Materials

Blood

Blood (Wet)

1. Large amounts or pools:

a. Use an eyedropper or hypodermic syringe to collect the fluid and transferto a sterile container (5 cc is sufficient for testing purposes).

b. Transfer immediately to laboratory or refrigerate specimen. However, donot freeze blood.

c. In some instances, depending on the jurisdiction regulations, a chemicalpreservative such as sodium azide or EDTA can be used to prevent blood spoilage.

2. Small amounts of wet blood:

a. Use a 100% cotton swab, #8 cotton thread, or gauze pad to collectspecimen.

b. Allow swab or gauze pad to air dry.

c. Place in sterile test tube or other clean container.

Figure 17.1 POOL OF BLOOD AT CRIME SCENE. This photo depicts a large pool of blood in the scene. The victim had been shot in the head with a large caliber weapon. Note that the blood has begun to separate, producing a straw-colored serum to the left of the stain. This serum usually appears approximately 20 minutes after the blood has leaked from the wound. (From the author's files.)

Figure 17.2 CLEAN-UP ATTEMPT. A clean-up attempt at this homicide scene is evident by the swirling patterns, which obliterated most of the footwear impressions at this scene. A remaining impression is partially visible under the victim's knee and another is visible in the center of the photo. Large bloodstains, drying at the surface only, were disturbed during the clean-up as can be noted at the lower right of the photo. This drying gave investigators a rough time estimate between the homicide and clean-up. (Courtesy of Yonkers, New York, Police Department Crime Scene Unit, Detective Lieutenant Peter Pizzola, commanding officer.)

Figure 17.3 RECONSTRUCTION — BLOOD PATTERNS. Sequential evidence such as this barefooted bloodstain trail and blood drip pattern can inform the investigator about events and movement through the scene, aiding in reconstruction of the crime scene. (Courtesy of the Westchester County, New York, Medical Examiner's Office.)

Figure 17.4 BLOODSTAIN BEING SWABBED AT SCENE. This photo illustrates the proper method for swabbing a dried bloodstain while processing the crime scene. Note that the ERT is wearing protective clothing to prevent cross contamination. (Courtesy of Detective Mark Czworniak, Chicago Police Department.)

Blood Stains (Dry)

1. Nonporous surface:

a. If there is sufficient amount of dry blood, it can be scraped from thesurface with a clean razor blade or sterile scalpel. These scrapings should be shaved into a sterile container.

2. Porous surface (fabric, unfinished wood, etc.):

a. Collect and submit the article containing the stain to the laboratory asfound.

b. Wrap in separate and sterile container. If the article is too large or inap-propriate to transport, remove a portion of the material containing an adequate amount of the stain for transport to the laboratory for analysis. 3. Traces or smears that cannot be scraped into container:

a. Moisten a 100% cotton swab or gauze pad with distilled water. Stain willsoften and soak into swab or gauze pad. Also obtain a control sample, which should be forwarded to the lab for analysis with the specimen.

b. Allow to air dry.

c. Place into a sterile test tube or container for the laboratory.

Remember: Do not use a swab or other instrument to collect blood from more than one stain. Use separate swabs, razors, scalpels, or other instruments for each separate stain to be sampled. This is to prevent contamination of samples.

Figure 17.5A PHENOLPATHLEIN. Phenolphthalein is a presumptive blood test. The swab is moistened with dionized water. Swab the area of interest with the dampened swab. Add one or two drops of phenolphthalein. Then add one or two drops of hydrogen peroxide. If blood is present, the swab will turn a purple/fuchsia color immediately. (Courtesy of David Rossi, CSI/SCSA, Harris County,

Texas, Sheriff's Department.)

Figure 17.5B LEUCOMALACHITE GREEN

(LMG). Leucomalachite green (LMG) is a colorimetric test used to screen for the presence of blood. The sample is swabbed and the chemical LMG is added to the swab. Next, hydrogen peroxide is applied to the swab. If there is blood present, the swab will turn green, indicating a positive result. No color change indicates a negative result (no blood present). (Courtesy of Fred Drummond, chief of Forensic Sciences, Westchester County, New York, Forensic Laboratory. Photographer: Carlos Morales.)

It is possible that the assailant's blood may also be present. If the same instrument is used to collect all samples, the evidence will be tainted. Furthermore, you should be careful not to touch the surface that has contacted the blood sample because your secretions may contaminate the collected sample (see Chapter 16, "Forensic Application of DNA Analysis").

Field Test Reagents. Tests for the presence of blood:

Phenolphthalin (Kastel–Meyer). This test is performed by rubbing a cotton swab that has been moistened in a saline solution on the suspected blood stain. A drop of phenolphthalin is added to the swab and then a drop of hydrogen peroxide 3% is added. A positive reaction will turn the swab pink to red within 15 seconds.

Leucomalachite green (LMG). This test is performed the same way as the preceding one. A positive reaction is indicated by a greenish-blue color that will appear almost immediately.

Luminol. This reagent is sprayed onto the object to be checked. However, it must be viewed in total darkness. A positive reaction will luminesce violet within 5 seconds.

Orthotolidine. This test is performed by rubbing a cotton swab that has been moistened in a saline solution on the suspected blood stain. A drop of

(A) (B)

Figure 17.6 APPLICATION OF LUMINOL. (A) The interior of a vehicle used in a homicide prior to the application of luminol. (B) The interior of a vehicle used in a homicide after the application of luminol. Note the bright blue color, which indicates a positive reaction to blood. (Courtesy of Frederick C. Drummond, chief, Westchester County Forensic Science Laboratory,

Valhalla, New York.) orthotolidine is added to the swab and then a drop of hydrogen peroxide 3% is added. A positive reaction is indicated by an intense blue color.

Tetramethylbenzidine (TMB). This is another in a series of presumptive tests that is specific for blood. TMB is an enhancement reagent. The tetramethylbenzidine reacts with the heme in the blood. Spray the surface lightly two to three times about 10 inches away from the surface. The bloody imprint

Figure 17.7 APPLICATION OF FLUORESCEIN. This photo illustrates the application of fluorescein. The man's hand, which had blood on it, was washed and applied to this cloth. The cloth was then treated with fluorescein. (Courtesy of David Rossi, CSI/SCSA, Harris County,

Texas, Sheriff's Department.) pattern should turn a greenish-blue. Overspray may give a very dark blue pattern and mask ridge patterns.

Hemaglow. This is a protein reactant, which does not ordinarily react with household cleaners like luminol does. Hemaglow also glows more brightly and can be photographed with a flat-plane camera.

Leucocrystal violet (LCV). This is a new positive blood identifier that turns permanent violet when in contact with blood. Leucocrystal violet can be testified to in court as a blood identifier at the scene without further testing to identify the stain as blood.

Fluorescein. The chemical mixture of fluorescein causes a catalytic reaction to occur between the hemoglobin in blood and oxygen. This produces a luminescent stain, which will luminesce in the dark when excited under ALS. The major advantage is that it will continue to luminesce for hours under UV or ALS after the initial application and without additional applications of the reagent.

Tests for the presence of body fluids:

Semen Acid phosphatase tests

Urine Amylase tests

Saliva Creatinine, urea tests

Fecal matter Urobilinogen

Gastric contents Gastric acid

It should be noted that the preceding chemical reagents (LCV and LMG) DO NOT allow for DNA typing when blood is found in small amounts.

Figure 17.8 EXAMINATION IN LABORATORY. A forensic scientist examines evidence. Protective clothing must be worn at all times during evidence examination in order to preserve the evidence and prevent contamination. It also protects the examiner from exposure to any harmful agents. (Courtesy of Fred Drummond, chief of Forensic Sciences, Westchester County, New York, Forensic Laboratory. Photographer: Keith Mancini.)

Semen

Next to blood, semen is the physiological fluid most commonly discovered at homicide crime scenes. If a sexual assault is suspected, the investigator should carefully examine the body and clothing of the deceased prior to moving the body. If any stains are observed, procedures to collect this evidence should be performed at the scene. Later at autopsy, the medical examiner or coroner will take a vaginal swab or vaginal aspirant to obtain any semen traces from within the vaginal canal. In addition, oral and anal swabs may be taken, if sodomy is suspected, and air dried immediately.

The following techniques should be employed at the scene:

1. Wet stain:

a. Swab or wash (by medical examiner if possible).

b. Draw the fluid into an eyedropper or hypodermic syringe.

c. Place in sterile test tube.

Figure 17.9 USE OF ALTERNATE LIGHT SOURCE. This photo illustrates the use of an alternate light source (ALS). The forensic scientist is examining clothing for body fluids not visible under normal lighting conditions. (Courtesy of Fred Drummond, chief of Forensic Sciences, Westchester County, New York, Forensic Laboratory. Photographer: Carlos Morales.)

Figure 17.10 ACID PHOSPHATASE TEST. Acid phosphatase (AP) is an enzyme present in various body fluids, but is typically found in high concentrations in semen. A positive result causes a color change in the plate in shades of purple. This photo illustrates a positive finding. (Courtesy of Fred Drummond, chief of Forensic Sciences, Westchester County, New York, Forensic Laboratory. Photographer: Carlos Morales.)

Figure 17.11 DRIED SEMEN EVIDENCE. This close-up photo of the vaginal area of a rape–homicide victim discloses traces of dried semen. (See arrow.) Notice the "starchy" appearance. This trace should be gathered using 100% cotton moistened with distilled water, which should be allowed to air dry and then placed in a sterile container for delivery to the laboratory.

(From the author's files.)

d. Use swab or cotton gauze pad for samples of smaller quantities that arestill moist.

e. Allow to air dry immediately and place in sterile container.

2. Dry stain:

a. Dry stain will have a stiff "starchy" texture.

b. If it is on clothing, submit the entire article, being careful not to breakor contaminate the stained area.

c. On body, using 100% cotton gauze pad moistened with distilled water,gently remove stain and place in sterile test tube or container after allowing to air dry.

Sometimes an ultraviolet light or certain wavelengths of an alternate light source (ALS) can be used to locate seminal stains. However, in many instances, a false reading will be obtained due to the "brighteners" used in certain laundry detergents as well as the fact that numerous other items will also fluoresce. It should also be

Figure 17.12 WET SEMEN STAIN. This offender had masturbated on this victim after strangling and hanging her by the neck. He left wet semen stains on the victim's blouse. (Courtesy of Captain Steve Denton, CID, Spartanburg County, South Carolina, Sheriff's Office.)

Figure 17.13 CRIME SCENE PHOTO — VICTIM'S PANTIES. Criminal sexual assault. This photo of the victim's panties was taken with conventional photographic flash. (Courtesy of Detective Mark Czworniak, Chicago Police Department.)

noted that UV can and does disrupt the structure of DNA. Caution should be exercised. (See Chapter 16, "Forensic Application of DNA Analysis.")

Urine

1. Remove by eyedropper, sterile cotton swab, or 100% gauze pad.

2. Place in sterile text tube or other container.

3. If on clothing, the entire article should be submitted.

Figure 17.14 PHOTO — VICTIM'S PANTIES WITH ALS. This photo was taken utilizing an alternate light source, which disclosed traces of semen. Note the stains that have fluoresced. Swabs should be taken from the areas that fluoresce and submitted to the laboratory for forensic examination. (Courtesy of Detective Mark Czworniak, Chicago Police Department.)

Saliva or Spittle

1. Remove with eyedropper, sterile cotton swab, or 100% gauze pad.

2. Place in sterile test tube or other clean container after drying.

Recovery of Saliva and/or Urine. The methods used in the recovery of saliva samples at a scene are dictated by the nature of the stain and the nature of the surface on which it is found. The surfaces on which such evidence is found might by porous or nonporous.

Porous surfaces such as clothing, unfinished wood, paper, cardboard, and many more fall into this category. Wet body fluids can be absorbed into the materials.

1. Stains (wet or dry) on porous surfaces that can be removed along with ample surface area surrounding the stain should be recovered.

2. Stains on surfaces that can be collected as an entire item should be collected in whole.

3. Wet stains should be allowed to dry before packaging.

Nonporous surfaces:

1. Collection of the entire item and removal of a section of the surface bearing the stain along with ample material surrounding the stain are two preferred methods of collection.

2. Nonporous surfaces bearing saliva stains may be susceptible to abrasive removal of the stain materials by any packaging if the stain is not protected.

3. Contamination through handling with uncovered hands or inadvertent rubbing should be avoided.

Figure 17.15 COLLECTION OF BUCCAL CELLS. This photo illustrates the proper method for collecting buccal cells from a suspect's mouth. (Courtesy of Detective Mark Czworniak,

Chicago Police Department.)

Remember: Saliva is more useful to the investigator today because DNA technology has become so advanced through the extreme sensitivity of techniques such as PCR. DNA from epithelial cells present in saliva can be swabbed from the surfaces of the oral cavity of suspects and has, in fact, become the method of choice in screening a number of suspects in an investigation. The swab method of extracting DNA is not as intrusive as taking blood samples and can be easily and quickly analyzed.

I have consulted on many sex-related homicide investigations where there have been a number of possible suspects. I recommend that the authorities consider obtaining buccal cells from as many persons as possible, which may lead to the positive identification of the offender through this nonintrusive method of acquiring a DNA sample. In the BTK case in Wichita, Kansas, the authorities requested persons of interest to submit voluntarily to buccal cell swabbing for the purposes of elimination.

Feces

1. Large amount:

a. Remove with a small clean shovel. Allow to air dry.

b. Place in sterile container.

2. Small amount:

a. Remove with 100% cotton swab or gauze pad moistened with distilledwater, then air dry or scrape into container.

b. Place in sterile test tube.

Figure 17.16 BUCCAL CELL COLLECTION KIT. (Courtesy of Detective Mark Czworniak,

Chicago Police Department.)

Vomit

1. Remove with eyedropper or small shovel, depending on amount.

2. Place into sterile container.

Tissue

1. Remove with tweezers.

2. Place in a glass container or sterile test tube.

3. Forward to the medical examiner.

It should be noted that any physiological fluid found at the scene, such as urine, saliva, feces, perspiration, ear wax, or nasal mucus, can be typed into the same grouping as blood providing the material comes from an individual who is a secretor. Secretors make up approximately 80% of the general population. Physiological fluids of these secretors can be blood typed by the serologist. Other genetic factors sometimes can also be identified regardless of secretor status.

Remember: DNA/PCR technology provides the possibility of an individualistic comparison to a suspect as well as other genetic factors, which can also be identified regardless of secretor status.

Figure 17.17 HAIR EVIDENCE ON UNDERPANTS. This photo depicts various hairs on the suspect's underpants. (Courtesy of Detective Mark Czworniak, Chicago Police Department.)

Hair

During crimes of violence, specifically against persons, certain trace materials such as hair or fibers will be transferred between the victim and the perpetrator. These traces may also be left at the scene. Hairs are considered a class characteristic — although they cannot be identified as being absolutely identical to a given suspect's hair, they can be classified as similar to a known sample. In addition, they can be used to exclude a suspect. However, from an investigative point of view, hairs and/or fibers can

1. Help determine the extent of the crime scene

2. Place the perpetrator at the scene of the crime

3. Connect the suspect to the weapon

4. Corroborate statements of witnesses

5. Determine the route to and from the crime scene

6. Be located in any number of areas involved in the homicide:

a. The victim

b. The crime scene

c. The weapon

d. A tool

e. A vehicle

f. An article of clothing

g. The suspect

Figure 17.18 RECOVERY OF HAIR EVIDENCE. This photo depicts the proper recovery and collection of hair from the suspect's underpants. Note that the ERT is wearing protective gloves and is using tweezers. (Courtesy of Detective Mark Czworniak, Chicago Police Department.)

Figure 17.19 CONDOM RECOVERED AT CRIME SCENE. A "dry" condom was recovered at the crime scene. No fluids were present but pubic hairs were discovered inside the partially rolled condom. A few of the pubic hairs contained roots and were submitted for DNA extraction. (Courtesy of Detective Mark Czworniak, Chicago Police Department.)

Determinations from Hair.

1. Species — human or animal

2. Race — Caucasoid, Negroid, or Mongoloid (In certain instances, the determination of a combination of racial characteristics can be ascertained.)

3. Location of growth — body area from which the particular hair originated (head, thorax, chest, pubis, etc.)

4. Treatment — dyed, bleached, straightened, etc.

5. How it was removed — pulled, fell out, cut, etc.

6. Disease and/or damage

7. Genetic information: DNA analysis can link hair to a specific source. STR DNA analysis can be performed on hair, which could provide the authorities with the genetic fingerprint of the subject (see Chapter 16, "Forensic Application of DNA Analysis"):

a. Blood type, from shaft of hair

b. Other genetic markers, from roots of pulled hair

c. Sex, from roots of pulled hair8. Traces of drug use:

a. Drug molecules circulate in the bloodstream, seep into the hair and staythere. It has been scientifically established that the hair is the body's garbage can.

b. The drug molecules eventually find their way into the strands of hair.Analysis of these hairs using a mass spectrometer can provide authorities with a drug history of the offender.

It is recommended that a sample of hair from various parts of the body be obtained in all homicide cases. Even though hair evidence may not be crucial or known to exist in the early stages of the investigation, it may be discovered later after the body has been buried or destroyed through cremation. Samples should always be taken from various parts by pulling or plucking so as to obtain a piece of the root. If pulling or plucking absolutely cannot be undertaken for some reason, cutting the hair close to the scalp will suffice. An ordinary sampling will comprise approximately 24 to 48 pieces of hair. Hair removed from the head should be taken as follows: front, back, left side, right side, and top. The sample roots should then be air dried.

Collection of Hairs from the Scene. Use oblique lighting and/or ALS to scan the surfaces of the crime scene:

1. If hairs or fibers are located, gather by tweezers, being careful not to bend or break.

2. Masking or cellophane tape can be used to gather small fibers or hairs.

3. Place in sterile container and seal. (Folded paper or envelopes may also be used.)

Conclusions from Hair Samples.

1. Hair did not come from unknown hair source.

2. Hair could have come from known hair source.

3. Hair sampling is too limited for meaningful comparison.

4. No conclusion can be made.

Objects

Bullets

When a bullet is fired from a weapon, certain distinctive characteristics are imparted to the bullet by the gun. These markings can be examined through internal ballistics and provide the investigator with certain general information regarding the type of weapon used. In addition, ballistics evidence is highly individualistic, and a fired bullet recovered from the scene can be positively matched with the suspect weapon.

1. Bullets should be collected without damaging or marking the rifling — the series of grooves or lines on the interior surface of the barrel, which cause the bullet to spin and travel forward through the barrel with accuracy. These grooves and lines are transferred to the bullet as it is fired and are used by the ballistics expert to make comparisons.

2. Bullets embedded in doors, trees, walls, etc., should be removed by taking out a portion of the object in which the bullet has become lodged rather than by probing or digging. Digging for the bullet may cause additional marks, which may destroy the ballistics value of the evidence.

3. Recovered bullets should be examined for blood or other materials before packaging.

4. Bullets should be marked on the base or nose.

5. Each bullet should be packaged separately in an appropriate container, preferably one that will prevent any cross-contamination or accidental abrasion of the rifling marks.

6. Package should be marked to show identification and location of discovery.

Figure 17.20 MARKING BALLISTICS EVIDENCE. Recommended procedure. Mark on the base and nose of the projectile. (Courtesy of Medical Legal Art. Illustration copyright 2005, Medical Legal Art, www.doereport.com.)

Discharged Casings or Cartridges

The recovery of discharged shells may indicate the direction and location of the attack as well as how many shots were fired. In addition, certain class characteristics such as make and caliber can be ascertained. Furthermore, if an automatic weapon was used, certain ejector or clip markings may be present.

1. Recovered casings should be marked on the inside wall of the shell by the mouth or, if this is not possible, as near to the opening as possible.

2. Never mark the recovered casing on or near the end, which contains the primer cap, because examination of weapon markings may be destroyed.

3. Always consider the possibility of fingerprints on the sides of these casings and take appropriate methods to preserve them.

4. Package in separate containers with proper documentation.

Shotgun Shells

1. Plastic or paper shotgun shells should be handled in the same manner as other discharged casings.

2. These items can be marked on the metal side part of the casing.

3. Never mark on the base of a shell casing.

Live Cartridges or Rounds of Ammunition

1. Examine for fingerprint evidence prior to marking.

2. Mark on side of casing.

3. Package, indicating the location of recovered rounds.

Shotgun Wadding

1. Recover and submit for laboratory examination.

2. Place in a separate container.

Weapons

1. Photograph and examine for fingerprints.

2. Examine for any serology or other trace evidence.

3. Place in special container, according to size, to protect evidence and prevent handling.

4. Forward to serology or crime lab for further analysis.

Firearms

1. Photograph in original position.

2. Examine for fingerprints.

Figure 17.21 FINGERPRINT ON WEAPON. (Courtesy of Detective Mark Czworniak, Chicago Police Department.)

Figure 17.22 CLOSE-UP BLOWBACK ON GUN BARREL. Death investigation: close up showing blood spatter blowback on revolver muzzle. (Courtesy of Detective Mark Czworniak, Chicago Police Department.)

3. Examine for any serology (e.g., blowback of close-range firing may result in blood, hair, or tissue being transferred to weapon or in barrel of weapon).

4. Upon completion of preliminary examination for the preceding, unload weapon and render it safe before transporting.

5. Package individually in an appropriate container. (In circumstances in which the firearm must be transported for further examination at a proper facility,

Figure 17.23 POSITIVE COMPARISON — CARTRIDGE CASE. Positive comparison of two .44 magnum caliber discharged cartridge cases. The individual characteristics of each discharged cartridge case consist of horizontal breech face markings and a unique firing pin indent. (Courtesy of Detective Sergeant Frank Nicolosi and Detective Sergeant Anthony Tota,

Westchester County, New York, Police Department's Ballistics Unit.)

use a cardboard box. Draw a string through the trigger guard and attach this string at either end of the box, leaving the gun in a suspended position. For larger firearms such as rifles or shotguns, cut a notch in each end of the box and lay weapon across container.)

6. Indicate the brand name, model designation, serial numbers, caliber, and number of shots the weapon is capable of firing, e.g., 5- or 6-shot revolver, in reports and on evidence containers. Also indicate the type of finish — nickel plate, etc.

7. All weapons recovered should be marked for identification as soon as possible in the following manner:

a. Revolvers — mark on frame, barrel, and cylinder.

b. Rifles and shotguns — mark on receiver, bolt, and barrel.

c. Semiautomatic weapons — mark receiver (frame), slide, barrel, andany clips.

Forensic Examination of Firearms and Ballistics. The Integrated Ballistic Identification System (IBIS) developed by Forensic Technology, Inc. is an image analysis system for acquiring, storing, and analyzing the images of bullets and cartridge

Figure 17.24 POSITIVE COMPARISON — BULLETS. Positive comparison of two .45 caliber copper-jacketed bullets. The individual characteristics on each bullet include striations that appear on the land and groove areas. The striae that appear on these bullets are accidental in nature and unique to a particular firearm. (Courtesy of Detective Sergeant Frank Nicolosi and Detective Sergeant Anthony Tota, Westchester County, New York, Police Department's Ballistics Unit.)

Figure 17.25 MOUNTED .45 CALIBER BULLET. Right-hand stage of the comparison microscope with .45 caliber copper jacket bullet mounted to the wax holder, ready for examination and comparison. (Courtesy of Detective Sergeant Frank Nicolosi and Detective Sergeant

Anthony Tota, Westchester County, New York, Police Department's Ballistics Unit.)

Figure 17.26 LEICA DMC COMPARISON MICROSCOPE. Detective Sergeant Frank Nicolosi is using this microscope, which consists of two optically paired microscopes connected to an optical bridge that allows the user to observe two objects simultaneously with the same degree of magnification. (Courtesy of Detective Sergeant Frank Nicolosi and Detective Sergeant Anthony Tota, Westchester County, New York, Police Department's Ballistics Unit.) cases. IBIS® is Forensic Technology's cornerstone product. The system is composed of two modules:

BULLETPROOF® for bullets

BRASSCATCHER® for cartridge cases

The system captures video images of bullet striations and the markings left on cartridge cases, which produce an electronic "signature" stored in a database. Networking hardware and software allow transfers and comparisons of forensic evidence from different cities and countries.

• Unique characteristics of groove marks can be found on spent bullets.

• Unique characteristics left on cartridge cases are recorded.

• Evidence is read by laser and coded for computer storage.

• Results are entered into the data bank.

• Comparisons with an entire database of fired bullets/cartridges are possible.

• Networking hardware and software allow transfers and comparisons of forensic evidence from different jurisdictions.

BrassTRAX™ is an automated, desktop cartridge-case acquisition station for collecting digital images of cartridge-case evidence for cataloging and comparison

Figure 17.27 INTEGRATED BALLISTIC IDENTIFICATION SYSTEM (IBIS). This photo depicts the IBIS Hub, which comprises a data acquisition station (DAS) networked to a correlation server and signature analysis station (SAS). The DAS enables users to acquire images of bullet and cartridge case evidence using an automated microscope and digital imaging technologies. Images collected by DAS are given a unique "digital signature" and sent to the correlation server for comparison and storage. The correlation server mathematically compares digital signatures from the DAS and ranks them according to the degree of similarity. Correlation results can be reviewed on the SAS. The SAS provides examiners with the ability to view and analyze results from the correlation server. Proprietary software utilized by the SAS enables users to sort and filter massive amounts of ballistics evidence, concentrating on only the most likely matches. (Courtesy of Forensic Technology, Inc., 888/984-

4247, www.forensictechnologyinc.com.)

within an IBIS correlation server. Because of its simplified design, BrassTRAX can be operated with little or no specialized training. Its advantages include:

• Scalable cartridge-case acquisition stations that can be added to an IBIS hub or data concentrator

• Getting evidence into the analysis process quickly

• Minimal user training and expertise to operate

• Desktop-sized unit

• Efficient local area network and wide area network connections

• Increased automation reduces operator variances

BulletTRAX-3D™ is a bullet-evidence acquisition station that uses the latest in three-dimensional imaging technology. BulletTRAX-3D utilizes a specially designed microscope that can capture a digital image and create a three-dimensional topographic model of the surface of a bullet. This information can then

Figure 17.28 EXAMINATION. Detective Arthur R. Holzman makes comparisons at IBIS station. (Courtesy of Detective Sergeant Frank Nicolosi and Detective Arthur R. Holzman, Westchester County, New York, Police Department's Ballistics Unit.)

Figure 17.29 IBIS COMPUTER STATION. (Courtesy of Detective Sergeant Frank Nicolosi and Detective Arthur R. Holzman, Westchester County, New York, Police Department's Ballistics Unit.)

Figure 17.30 IBIS BULLETPROOF FOR BULLETS. Screen depicting side-by-side comparison of bullets. (Courtesy of Forensic Technology, Inc., 888/984-4247, www.forensictechnology inc.com.)

be sent to a centralized IBIS correlation server. The advantages of BulletTRAX3D include:

• Ability to take quantitative measurements of a bullet's surface

• Scalable acquisition station that is compatible with other IBIS solutions

• Minimal user training and expertise to operate

• Environmental conditions (light intensity, orientation, type) can be modified after the acquisition process

• Increased correlation accuracy

Forensic Technology, Inc., can be contacted at www.forensictechnologyinc.com.

Gunshot Residue Testing. See "Gunshot Residue Testing" in Chapter 8.

Fibers

Fibers, like hairs, may be transferred between the victim and perpetrator and provide the investigator with an additional piece of class evidence which can be subjected to microscopic and microchemical testing. Cross-transfers of fibers between victims and offenders are particularly common in incidents of rape and other physical assault and in homicides committed by strangulation, blunt force

Figure 17.31 IBIS BRASSCATCHER FOR CARTRIDGE CASE. Screen depicting side-byside comparison of cartridge cases. (Courtesy of Forensic Technology, Inc., 888/984-4247, www. forensictechnologyinc.com.)

trauma, stabbing, and other means involving close physical contact. Items such as fibers, rope, string, or twine should be collected for examination. Fibers and threads from clothing, blankets, rugs, and other common woven objects also have their unique colorations and patterns that can be identified in meticulous detail during the laboratory process.

1. Examination of fibers will indicate origin as follows:

a. Vegetable — e.g., cotton and hemp

b. Animal — e.g., wool and mink

c. Mineral — e.g., glass wool and asbestos

d. Synthetic — e.g., nylon and orlon

2. Examination of fiber evidence will determine whether the fiber is similar to the control sample.

3. Collect fibers as follows:

a. Forceps

b. Tape

c. Vacuum sweeping (note that this is the least desirable method becausetoo many contaminants are also collected)

4. Collecting samples by using sticky side of tape is considered the most practical method.

Figure 17.32 EXAMINATION FOR TRACE EVIDENCE. Forensic scientist Daniel Rothenberg examines trace evidence under a stereomicroscope, which provided a three-dimensional image. (Courtesy of Fred Drummond, chief of Forensic Sciences, Westchester County, New York, Forensic Laboratory. Photographer: Keith Mancini.)

Place samples in individual containers from each area gathered, mark appropriately, and forward to the laboratory for examination.

Fabric

1. Pieces of fabric found at the scene can be examined in a manner similar to fibers to determine: a. Color

b. Type of cloth and fiber

c. Thread count

d. Direction of fiber twist

e. Dye

2. Class as well as individual characteristics can be obtained from fragments of fabric when matched by physically fitting the evidence pieces into its source.

3. Reconstruction of an event based upon fiber transfer is possible. (See Figure

17.33A through D.)

Cigarette/Cigar Butts

Cigarette or cigar butts found at the crime scene, especially those with filter tips, can be examined by serologists for the determination of blood type and sometimes other genetic factors (e.g., sex) of individuals who are secretors. (Also, see Chapter 16, "Forensic Application of DNA Analysis.")

(A)

(B)

Figure 17.33 FIBER EXAMINATION — RECONSTRUCTION. In this case, a woman and her two children were stabbed to death. A third child was stabbed but survived. The suspect (the woman's boyfriend) was also stabbed. He claimed that he was stabbed when he tried to stop the woman from stabbing her children. He claimed that he wrestled the knife away from the woman and stabbed her in self-defense. (A) Bra from victim #1, which showed tears from knife. (B) Magnified image of exemplar nylon fibers from victim's bra. (C) Shirt from child homicide victim #2. (D) Magnified image of nylon fiber recovered from one of the stab marks in the child victim #2's shirt. This fiber was consistent with the fibers from the bra of victim #1. This showed a sequence of stabbings. Victim #1 was stabbed first and the knife was subsequently used on victim #2. This disproved the suspect's statement. (Courtesy of Fred Drummond, chief of Forensic Sciences, Westchester County, New York, Forensic Laboratory. Photographs courtesy of Ted R. Swartz and Mary M. Eustace. Photographers: Ted Swartz and Keith Mancini.) Continued.

(C)

(D)

Figure 17.33 Continued.

Figure 17.34 CIGARETTE BUTT AT CRIME SCENE. This photo shows a partially smoked cigarette butt lying in the snow. The cigarette butt depicts lipstick and has apparently burned out in the snow. Investigators who were searching the area where a body had been found discovered this piece of evidence. In fact, the cigarette's condition was consistent with the time the body had been lying at the location. This victim was discovered shortly after being shot. It is important to note that DNA can be obtained from the saliva transferred to the cigarette. In this case, it matched the victim. (From the author's files.)

1. Collect with forceps or tweezers and ensure dryness.

2. Place into separate containers to prevent contamination.

3. Containers should be appropriately marked.

4. Forward to serology and/or DNA laboratory

Displaced Furniture

1. Examine for any fingerprints or serology.

2. This can be useful in crime reconstruction.

Soil

1. Soil on shoes, clothing, tools, weapons, and other objects may be useful in placing a suspect at the scene and providing the investigator with additional evidence. Also, microbiological comparisons in addition to mineral comparisons can be made.

a. Color of soil may be distinctive.

b. Minerals can be distinctive.

c. Bacterial profiles can be distinctive.

d. Vegetation (fungal spores, etc.) can be distinctive.

2. Collection of soil samples:

a. Collect several samples at the scene from various locations because min-eral and organic contents vary within short distances.

Figure 17.35 SAND ON SUSPECT'S VEHICLE. The suspect's vehicle revealed sand on the tires and the rocker panel, which matched the sand at the beach where he had buried the body. (Courtesy of Detective Corporal Arthur Clark, East Providence, Rhode Island, Police Department.)

Figure 17.36 SAND RECOVERED INSIDE SUSPECT'S VEHICLE. Detectives located sand, fibers, and blood in the trunk of the suspect's car, linking him to the body buried on the beach. (Courtesy of Detective Corporal Arthur Clark, East Providence, Rhode Island, Police

Department.)

b. Gather at least a cupful or handful from each location.

c. Ensure dryness.

d. Package in separate containers.

e. Mark properly for identification and location.

Tools

Tools suspected of being used in the crime should be examined as follows:

Figure 17.37 EXAMINATION OF SUPECT'S VEHICLE. This photo shows the interior of the suspect's minivan. The minivan had been used in a kidnapping and had apparently been cleaned by the suspect. (Courtesy of Fred Drummond, chief of Forensic Sciences, Westchester County, New York, Forensic Laboratory. Photographs courtesy of Kevin MacLaren. Photographer: Keith A. Mancini.)

1. Examine for serology or fingerprints.

2. If the tool contains any serological evidence, it must be carefully packaged to preserve this evidence.

3. If the tool contains traces of certain materials that are to be matched up with known samples, care must be taken so that this material is not rubbed off.

4. The portion of tool to be matched must be protected.

5. Broken tools and/or knives can be fracture matched to provide positive identification.

6. Never try to fit a tool into a tool mark or match broken pieces together.

Vehicles

1. Photograph and examine for serology.

2. Process for fingerprints.

3. Examine for other items of evidence.

4. Search for weapons.

Clothing

Each item of clothing collected as evidence should be individually wrapped in order to prevent cross contamination. If the clothing to be collected is wet, it should be air dried before it is packaged. Clothing may provide the investigator with additional evidence as follows:

Figure 17.38 SUSPECT'S VEHICLE AFTER ALS. An alternate light source was used to view the interior of the van. Areas of the van fluoresced at 435 nm showing areas of possible cleaning with detergents. (Courtesy of Fred Drummond, chief of Forensic Sciences, Westchester County, New York, Forensic Laboratory. Photographs courtesy of Kevin MacLaren. Photographer: Keith A. Mancini.)

1. Stains on clothing may match stains from the scene, the victim, or the suspect.

2. A suspect's clothing may contain blood similar to the victim's.

3. The victim's clothing may contain saliva and/or seminal fluid from the perpetrator.

4. Hairs or fibers may be present on clothing that match similar hairs or fibers from a particular scene or location or from the victim.

5. Tears or cuts made by the weapon in clothing can be matched to show the position of the victim at the time of the assault.

6. The deposit of gunshot residues on clothing can be analyzed to determine the approximate distance from which the gun was fired.

Documents (Letters, Notes, Papers)

These items may be examined to ascertain authenticity, locate fingerprints, or determine authorship in suicide cases, or for more advanced techniques such as psycholinguistic examination. (See "Psycholinguistics" in Chapter 20.)

1. The primary consideration in handling this type of evidence is the preservation of any fingerprints that may be on the item.

2. Evidence should be collected by using tweezers or forceps to pick up the paper gently.

3. Each item should be placed in a separate package. A clear or see-through package is best because it will allow the investigator to examine contents without contaminating the document with additional fingerprints.

4. If see-through packages are not available, the object can be photocopied using forceps to place the object on the machine and later to transfer it to the evidence envelope. (This will allow for reading and other examination of content without disturbing evidence value of the original document.)

5. Marking this type of evidence depends on the type of examination to be conducted. In some instances, a mark can be placed on a back corner of the paper. In other instances, just the package into which the document is placed will be marked.

6. Documents should not be folded.

7. Examine for latent prints.

8. Saliva on envelopes can be blood typed and sometimes analyzed for sex origin.

Examination of Documents. The examination for latent prints on papers, documents, and other porous materials such as wood proceeds in a series of steps:

First step: iodine fuming — reacts with oil or fatty fluids in latent print.

Second step: ninhydrin — penetrates material and reacts with amino acids in perspiration. Heat should be applied and print will emerge.

Third step: silver nitrate — reacts to salt in the perspiration. The document is then exposed to strong light.

Glass

Glass fragments are often recovered as trace evidence during criminal investigations. Because of the many different types of glasses manufactured, the challenge for the forensic examiner is to uniquely identify and characterize the glass trace evidence material from a crime scene with a high level of certainty that is defensible. Characterization of glass fragments is normally accomplished by measuring the physical and optical properties of density and refractive index.

Examinations conducted on glass and glass fragments using a refractive index to prove that the known sample and the evidence glass may have come from a similar source has become more difficult as the range of refractive indices has narrowed within glass subtypes because of advances in glass manufacturing technology. Glasses from the same subtype, which have the same gross elemental composition, can have different trace and ultratrace elemental signatures.

According to Dr. David Baldwin, Ames Laboratory,1 scientists have investigated the use of elemental analysis techniques, particularly inductively coupled plasmaatomic emission spectrometry and plasma-mass spectrometry, for discrimination or differentiation of glasses within a particular class (e.g., window glass) based on their trace elemental content.

Contact information: (515) 296-6372, [email protected].

Technology Description.2 Laser ablation inductively coupled plasma-mass spectrometry is an analysis technique that can differentiate glass fragments, which have similar refractive indices, based on the unique trace elemental signatures of the glass samples. Glass can now be positively and forensically identified with a specific source. Lasers zap the glass fragments, which evaporate the particles into smoke. Then a gas sweeps the particles into hot plasma that allows the examiner to see a unique chemical makeup. The technique is so precise that the glass particles can be traced to a specific manufacturer. Microscopic shards of glass found in a suspect's hair, shoes, or home can be matched to a crime scene.

Additionally, criteria and protocols for the comparison and differentiation of glass fragments from different sources, based on multivariate analysis techniques, have been developed. Laser ablation-ICP-MS is a powerful and versatile technique for determining the elemental composition of a variety of different types of samples.

Furthermore, the direction and sequence of bullet holes through glass can be determined by examination of radial and concentric fractures and may prove important in reconstructing the crime.

Glass should be collected as follows:

1. Small pieces should be placed in a vial or pillbox.

2. Large pieces should be placed in a sturdy cardboard box with proper padding or protection to prevent further breakage during transport.

Figure 17.39 INSIDE WINDOW — SHOTS FIRED THROUGH GLASS. Multiple homicide scene. Witnesses described two offenders who began shooting through the open doorway of a crowded night club. Evidence collected inside the club indicated that shots had also been fired from inside the club toward the first two shooters. Everyone inside the club denied that shots had been fired from inside. Bullet holes were discovered in the plate glass windows at the front of the club. The inside window depicted in this photograph has a nearly symmetrical hole in the glass. (Courtesy of Detective Mark Czworniak, Chicago Police Department.)

Figure 17.40 OUTER WINDOW — SHOTS FIRED THROUGH GLASS. The outer window has an irregularly shaped hole caused by the bullet beginning to tumble after exiting the inside window — proof that shots were fired from inside the club and out toward the plate glass door. (Courtesy of Detective Mark Czworniak, Chicago Police Department.)

Impressions

Fingerprint Examination

The most valuable evidence that an investigator can obtain from the homicide crime scene is the fingerprints of the suspect. From an investigative point of view, any crime scene search should include a detailed examination for visible, plastic, and latent prints. It is important to note that the officer performing this function should preserve all developed prints. Even partial prints, which may seem insignificant, may become valuable later when compared with prints taken from a suspect. It should be noted that fingerprint powders do not interfere with serological analyses. However, ninhydrin sprays and other chemical means to make prints visible may interfere with DNA or serology tests. DNA can be obtained from fingerprints, and current technology will soon patent this new extraction technique.

Automated Fingerprint Identification Systems (AFISs). Utilization of automated fingerprint identification systems (AFISs) has significantly advanced the ability of law enforcement to identify and apprehend criminals whose prints are in various databases. Several AFIS technologies are in use across the United States, which can be problematic because the investigator may need to submit a questioned latent to more than one AFIS database. However, AFISs have revolutionized the manner in which police departments search latent prints for matches. Entire databases containing hundreds of thousands of fingerprints can be searched

Figure 17.41 AFIS — LATENT PRINT. Fingerprints such as this coupled with computerized automated fingerprint identification systems (AFISs) can be a rapid and precise way for the investigator to place an individual at a crime scene or tie two or more events to one offender. (Courtesy of Fred Drummond, Chief of Forensic Sciences, Westchester County, New York,

Forensic Laboratory. Photographer: W. Reid Lindsay.)

within minutes. Latent prints recovered from a crime scene can be computer matched to a criminal fingerprint database. The success of these systems is due to the large databases maintained by a number of state law enforcement agencies as well as by the military and other government agencies, which maintain fingerprint databases on all personnel and employees.

Types of Fingerprints. Fingerprints are divided into three separate categories: plastic prints, latent prints, and visible prints.

1. Plastic prints. These impressions occur when the finger touches or presses against a soft pliable surface such as putty, gum, a newly painted area, the glue on a stamp or envelope, wax, flour, thick dust, soap, grease, tar, resin, or clay. A negative impression of the friction ridge pattern is produced, resulting in a plastic print.

2. Latent prints. These prints occur from natural skin secretions such as perspiration. When grease or dirt is mixed with the natural secretions, a stable print may be deposited on the surface. Latent prints, which are not visible, are usually found on objects with smooth or polished surfaces or on paper. The latent print is developed by dusting or chemical process. In some instances, these latent prints can be developed on rougher surfaces by using certain chemical processes.

3. Visible prints. These prints occur when the fingers, palms, or feet, which have been contaminated with a foreign substance, come into contact with a clean surface and are pressed onto the surface, leaving a print. The most common type is the dust print. However, substances such as ink, blood, soot, paint, grease, face powders, or oils contaminate the friction ridges of the fingers.

When they are pressed against another surface, an image is transferred.

Figure 17.42 PLASTIC PRINT. This photo Figure 17.43 LATENT PRINT. This print illustrates the "plastic print." The fingerprint was enhanced with amido black. (Complihas been photographed with the finger's ments of Sirchie Fingerprint Laboratory, Inc.,

impression in clay. (Courtesy of David Rossi, www.sirchie.com.)

CSI/SCSA, Harris County, Texas, Sheriff's

Department.)

Figure 17.44 VISIBLE PRINT. Also referred to as a patent print. This photo illustrates a bloody fingerprint on wooden surface. (Courtesy of David Rossi, CSI/SCSA, Harris County, Texas, Sheriff's Department.)

Development of Fingerprints. The most common and practical method of developing prints at crime scenes is through the "dusting" technique. This is done by dusting or spreading fingerprint powder with a brush over the surface of the object suspected of bearing prints. The choice of the color of the powder to be used depends on the background of the object to be dusted. If the object is dark or black, a light powder is used; conversely, if the object is light or white, a dark or black powder is used. The most common color powders are black, silver, gray, and white. However, fingerprint powders come in many other colors, which can be used to contrast with any background. The brushes available are composed of camel's hair, feathers, fiberglass, or nylon.

1. A small amount of powder is poured onto a clean piece of paper.

2. The brush is drawn across the powder and then tapped with the finger to remove excess material.

3. The surface of the object to be searched is then lightly brushed by the investigator, who uses curved strokes to locate prints.

The fingerprint powder adheres to the material and forms the latent print, which will first appear as a smudge and will require further treatment before it becomes a distinct print. This is done by brushing the powder parallel to the ridge structure of the print, being careful not to rub the print too hard. After the print is developed, it should be photographed first and then lifted.

Another method of dusting is done with magnetic powders. The Magna-Brush is dipped into the magnetic powder, which then adheres to the magnet in the brush. When the powder, which is actually fine iron filings, is evenly distributed

Figure 17.45 DUSTING METHOD. This photo illustrates "dusting" to develop a latent print. (Compliments of Sirchie Fingerprint Laboratory, Inc., www.sirchie.com.)

Figure 17.46 THE CU-5 POLAROID CAMERA. 1 × 1 camera. (Courtesy of the Polaroid Corporation.)

on the end of the brush, the investigator uses the applicator like any other fingerprint brush. The advantage of this method is that there is no mess or excess powder left on the object. The disadvantage is that the Magna-Brush method cannot be used on ferrous metals and is very expensive. The prints that are photographed and located are lifted in the same manner as those obtained with the regular fingerprint powder.

Preservation of Fingerprints. Prints found at the scene of a homicide should be immediately recorded by photography before any attempt is made to "lift" the print. This procedure is recommended in the event lifting is not successful or the print is damaged during attempts to remove it from the item on which it is found.

In addition, photography also makes it easier to introduce the fingerprint evidence into court because parts of the object that contained the print can be seen in the picture. The method of photography used will vary with the expertise of the technician. I recommend that the investigator use the Polaroid Spectra Close-Up kit. Likewise, the CU-5 1 × 1 fingerprint camera produced by Polaroid is excellent for photographing fingerprints. Polaroid produces a fixed-focus camera called the CU-5, which is ideal for this type of work.

It should be noted that, in addition to latent fingerprints, palmar (palm, wrist) or plantar (foot, toe) skin designs may also be found at the scene.

Remember: These impressions or prints can also be used to positively identify suspects and should be preserved accordingly.

Chemical Processes. In addition to the powders, a series of chemical procedures can be employed to develop latent prints. These are iodine fuming, cyanoacrylate (superglue) fuming, ninhydrin, and silver nitrate. Furthermore, there have been some remarkable results in developing latent prints by use of the laser. Practically speaking, the average investigator will not be employing these procedures. However, you should be aware of the availability of these methods in the event that further examination of evidence is necessary in order to discover and develop latent print evidence. For further information, see the U.S. Department of Justice, FBI Laboratory Division's "Processing Guide for Developing Latent Prints."

Pattern Enhancement Reagents. Sirchie Fingerprint Laboratories, Inc., produces many different enhancement reagents that can be used in the field as well as in the laboratory.

Figure 17.47 ENHANCEMENT REAGENTS. (Compliments of Sirchie Fingerprint Laboratory, Inc., www.sirchie.com.)

Protein Enhancement Reagents

Ninhydrin. Ninhydrin detects trace amounts of amino acids associated with body secretions. The amino acids are transferred with the sweat from the pores of a finger, palm, or sole of the foot. Amino acids are easily absorbed into absorbent and partially absorbent surfaces such as paper, unfinished wood, cardboard, or leather.

Coomassie brilliant blue (R250). Coomassie blue is a general protein that works well with bloodstains. It is a more sensitive, general protein stain than crystal violet stains.

Crystal (gentian) violet. Crystal violet works exceptionally well on adhesive surfaces such as tapes.

Amido black. This is a protein reactant that is sprayed onto the suspected area. Naphthol, the amido black powder, is mixed with glacial acetic acid and methanol. The formula is to mix 2 g naphthol, 100 ml glacial acetic acid, and 900 ml of methanol. The procedure is to set the prints with methanol, then spray the area with amido black. Rinse with 100 ml glacial acetic acid and 900 ml of methanol. Rinse with water. Clean with Clorox.

Fatty Acid, Elements, and Compounds Enhancement Reagents

Iodine fuming

Small particle reagent

Superglue (cyanoacrylate) fuming

Different superglue fuming devices are available for use in the crime scene and the laboratory. Superglue is usually effective on nonporous surfaces. The cyanoacrylate produces visible prints, which can then be dusted with fingerprint powder to further

Figure 17.48 CYANO-

ACRYLATE WAND. The Cynowand™ is a device that allows the crime scene investigator to process the scene by fuming the area several inches away from the suspect surface and sweeping the wand back and forth. Latent prints can be developed as they are fumed. (Compliments of Sirchie Fingerprint Laboratory, Inc., www.

sirchie.com.)

Figure 17.49 CYANOACRYLATE FUMING CHAMBER. The INSTA-FUME disposable fuming chamber creates an environment that provides crystal clear fuming bags that allow constant monitoring of the fuming process and eliminate clean up. (Compliments of Sirchie Fingerprint Laboratory, Inc., www.sirchie.com.)

enhance the image before photographing and lifting. The most effective method for fuming is to place the object in a fuming chamber. The use of alternate light sources (ALS) in conjunction with the pattern enhancement reagents is an excellent technique for visualizing the ridge patterns.

Tire Tracks and Footprints

These impressions may be left in various types of material. The footprint is the most common impression left at or near the scene of a crime. A footprint is formed when the foot or sole and heel of a shoe becomes contaminated with some foreign substance, such as blood, paint, or dust. A foot impression is formed like a tire track, when the foot or tire treads are pressed into some type of moldable material such as dirt, clay, or snow. Any such impression should be preserved and used for comparison with suspects or vehicles. Impressions may be identifiable by wear, damage, characteristic properties, or repair marks.

I recommend William J. Bodziak's textbook, Footwear Impression Evidence: Detection, Recovery, and Examination, second edition,3 as the all-inclusive source for the proper recovery and collection of this type of evidence.

Impressions should be collected in the following manner:

Figure 17.50A LATENT PRINT — CYANOCRYLATE. This photo depicts a latent fingerprint on a plastic bag that was developed with super glue and then stained with RAM (rhodamine 6G fluorescent dye) before illumination with UltraLite™ ALS. (Courtesy of CAO Group, Inc., Sandy, Utah.)

Figure 17.50B ULTRALITE ALS GLUE PRINT. This photo illustrates the effect of the UltraLite alternate light source using the BMT™ head, viewed through amber glasses and photographed through an amber filter. Extraordinary detail is maintained using this development method. (Courtesy of CAO Group, Inc., Sandy, Utah.)

1. Photograph: prior to photography, the impression should be cleaned of all foreign matter. Lighting should be employed so as to enhance the details. A scale of measure should be included in the photo. Then a long-range view and a close-up should be taken.

2. Casting: A casting kit containing the following materials should be available for use at the crime scene: a. Plaster of Paris (5 lb)

Figure 17.53 BODZIAK TEXTBOOK. Footwear Impression Evidence: Detection, Recovery, and Examination, second edition, CRC Press, Boca Raton, FL.

b. Mixing container (flexible for reuse)

c. Stirring stick

d. Reinforcement material (sticks, wire, etc. to hold form)

e. Shellac or plastic spray (to form soft earth or dust)

f. Oil spray (to serve as release agent) 3. Preparation for casting:

a. Clean out the loose material without disturbing impression.

b. Plastic spray to fix soil prior to plaster.

c. Build a form around impression to avoid run-off.

d. Gently pour plaster of Paris over impression.

e. Add reinforcement sticks as form builds.

4. Preservation of dust prints:

a. Photograph first.

b. Use a special lifter (black rubber with a sticky surface) placed sticky sidedown over the impression. Press on the impression and then remove lifter.

Remember: Do not overlook soil evidence which may later be found on a suspect's shoes.

In addition to obtaining castings, the investigator should collect soil samples from the location.

Figure 17.55 TIRE IMPRESSION. This photo depicts a 3-foot long cast of a tire impression using dental stone. (Courtesy of William J. Bodziak, supervisory special agent [retired], FBI Laboratory Division and author of Footwear Impression Evidence.)

Figure 17.56 TIRE TRACKS AND SHOEPRINTS IN SNOW. The track measurements were never measured as they should have been. The perpetrator and victim exited on the passenger side; only the perpetrator re-entered the vehicle and he did so on the driver's side. This is a good example of taking advantage of snow to document and reconstruct crimes. (Courtesy of William J. Bodziak, supervisory special agent [retired], FBI Laboratory Division and author of Footwear Impression Evidence.)

Figure 17.57 TIRE IMPRESSION IN SNOW. This photo depicts a tire impression in snow. (Courtesy of William J. Bodziak, supervisory special agent [retired], FBI Laboratory Division and author of Footwear Impression Evidence.)

Tool Marks

Tool marks, like footprints and tire tracks, may contain minute imperfections which are unique and can sometimes be microscopically compared with the tool or object in question. It is better if the investigator can remove the object bearing the tool mark. This can be done by removing the surface for submission to the laboratory. In instances where this would be impractical, the tool mark can be cast with a silicone rubber material. To collect tool marks:

1. Photograph (long-shot and close-up with Polaroid Spectra Close-Up kit or CU-5 1 × 1 fingerprint camera produced by Polaroid.

2. Cast with a silicone rubber casting after spraying surface with silicone release agent.

Bite Marks

Practically speaking, bite marks may be considered as tool marks and are valuable physical evidence. (See "Bite Mark Identification" in Chapter 20.)

Bullet Holes

1. In walls or furniture, first photograph and then examine trajectory.

2. In garments:

a. Photograph.

b. Safeguard for examination for powder residue.

c. Wrap (do not fold) and place in proper container. Direction of fire canbe ascertained by using a color test to determine presence of lead (the Harrison test).

Newly Damaged Areas

The presence of damaged furniture or other objects, and any other newly damaged areas is indicative of some sort of violence or struggle. Practically speaking, anything that is out of place, damaged, broken, moved, or otherwise suspicious should be documented:

1. Photograph

2. Process for DNA

3. Examine for any serology

4. Process for fingerprints

References

1. Baldwin, D., Ph.D. Telephone interview, March 29, 2005.

2. Baldwin, D. et al. "Laser Ablation Inductively Coupled Plasma-Mass Spectrometry of Forensic Glass Samples." Final Report. Report IS-5163 February 2003–January 2004.

3. Bodziak, W.J. Footwear Impression Evidence: Detection, Recovery, and Examination, 2nd ed. Boca Raton, FL: CRC Press, 2000.

Selected Reading

Bevel, T. and R. Gardner. Bloodstain Pattern Analysis: with Introduction to Crime Scene Reconstruction, 2nd ed. Boca Raton, FL: CRC Press, LLC, 2001.

Gardner, R.M. Practical Crime Scene Processing and Investigation. Boca Raton, FL: CRC Press, 2004.

Geberth, V.J. Practical Homicide Investigation: Tactics, Procedures, and Forensic Techniques, 3rd ed. Boca Raton, FL: CRC Press, Inc., 1996.

Geberth, V.J. Sex-Related Homicide and Death Investigation: Practical and Clinical Perspectives. Boca Raton, FL: CRC Press, 2003.

James, S.H., P.E. Kish, and T.P. Sutton. Principles of Bloodstain Pattern Analysis: Theory and Practice. Boca Raton, FL: Taylor & Francis Group, 2005.

Kirk, P.L. Crime Investigation, 2nd ed. New York: John Wiley & Sons, 1974.

Lee, H.C. and R.E. Gaensslen. Advances in Fingerprint Technology. Boca Raton, FL: CRC Press, 1993.

Lee, H.C., T. Palmbach, and M. Miller. Henry Lee's Crime Scene Handbook. San Diego, California: Academic Press, 2001.