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properly identified. Regardless of how well the latent print was developed and lifted, if the
card is not properly marked with all the data required or if the fingerprint specialist is not
furnished with the information required, the entire process may be a wasted effort. In
describing the exact place that the lift was made, it is sometimes helpful to draw a simple
sketch of the object. The sketch should be made on the fingerprint card that is sent to the
laboratory. The inclusion of corresponding numbers on both the lift and the sketch establishes
the location of the latent print.
X. Forensic Odontology
Forensic odontology (FO) has been defined as the intersection of dentistry with criminal and
civil laws. FO can make significant contributions in the following circumstances:
• Identifying missing/unidentified persons.
A. Identification of Missing and Unidentified Remains
Dentition is the arrangement of a person’s natural and artificial teeth. Like a fingerprint,
dentition is individual- characteristic evidence. Forensic dentists have established individual
B. Bite Marks
Most bite marks usually involve humans and are easily distinguished from those inflicted by
animals. Victims may be alive or dead. An avulsed bite is so forcible that a portion of the
body is detached. This may be a finger, a chunk out of someone’s arm, or some other portion
of the body.
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places, highly accurate laser scanners are being used to record bite marks, replacing casting.
C. Cheiloscopy
Cheiloscopy is the identification of individuals based on the pattern of wrinkles on their lips,
D. Reconstructed Identification
Sometimes called dental profiling, this tool is used when other means of identification are not
XI. Hair
Hair evidence is often found because both victims and suspects can transfer it to each other or
the scene; hair is easy to locate and recover, and it is durable. It may be found on ski masks used
by offenders, in head and pubic hairs of assailants and victims, as well as their clothing, hats, and
wigs. It may also be clutched in the hands and under the finger nails of victims.
A number of useful conclusions are possible from the examination of hair:
• Human or nonhuman origin.
• Limited determination of animal species.
• Determination of classic racial characteristics of the donor.
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When collecting hair standards, at least 30 should be collected from various portions of the head
(front, back, top, and each side) to ensure that all variations of texture, color, and length have
been properly sampled. At each site, half of the hairs should be pulled and the rest combed
lightly onto clean paper. Gloves should be worn and a clean comb used on each area of the body.
All areas of the pubic or other area should be thoroughly combed to dislodge foreign hairs and
other materials. Hair samples can be placed in a clean envelope, which is sealed and labeled.
Pillboxes and other tightly sealed containers are also acceptable in many labs.
Hair collection at the crime scene requires a different set of considerations regarding known and
questioned samples:
• Document by photos, the evidence log, and by diagram where the hairs were recovered.
• Do not submit wet hairs to the lab; they should be allowed to air dry.
• If they are firmly attached to an object, leave the hairs intact and submit the object.
XII. Blood
Blood was class-characteristic evidence until the introduction of DNA analysis in the early
1980s. Since then, there have been advances in how fast analyses can be completed.
Because of the frequency with which blood is encountered and the fact that DNA analysis can
provide individual identification, officers need to be alert in locating and protecting this type of
evidence.
A. The Appearance of Bloodstains
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If blood at the crime scene is fresh and relatively uncontaminated, identifying it as blood is
not difficult. If it is in some other condition, identifying blood merely by “eyeballing it”
B. Using Bloodstains to Reconstruct the Crime
Bloodstains (known as blood spatter) may take many forms at a crime scene. These forms are
not random but are produced by such factors as the type, location, and number of wounds
C. Locating Blood Evidence
The places at which the investigator will find bloodstains are virtually unlimited. One way of
locating blood evidence is the use of a presumptive or preliminary field test. Luminol, a
Only qualified medical personnel should collect blood samples from a person. The following
guidelines apply:
• Draw two 5-milliliter samples of blood in purple-stoppered tubes, the insides of which
are coated with EDTA, a preservative used to prevent coagulation.
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If there is fresh blood, absorb it on a clean cotton cloth or swab. If the blood is clotting or has
dried, use distilled water to moisten a cotton cloth or swab and then absorb the blood with the
moist surface. Leave a portion of the cloth or swab unstained as a control or blank sample. Let
The procedure for collecting fresh blood from most surfaces is the same as that previously
described for blood on a person. However, when blood is in a filled bathtub or some other
Allow fresh bloodstains on garments to air dry naturally; then fold the clothing with the crusts
intact. Do not fold clothing in a way that creases bloodstains because the creases may cause
them to become dislodged. As you fold the clothing, place clean paper between each layer.
Usually, bloodstained garments are found at the crime scene or retrieved from a hospital’s
emergency room.
When bloodstains are on a large immovable object, they can be collected, if fresh, by using
the cotton cloth or swab technique or by cutting a large sample from a dried stain. If there are
multiple stains on the object, use a new cloth or swab each time you switch from one stain to
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During warm weather, especially during daylight hours, blood evidence should not be locked
in car interiors or trunks because heat could rapidly degrade the evidence. If dried-blood
evidence is not submitted to the laboratory immediately, the garments, objects, and/or samples
taken should be refrigerated.
D. Laboratory Determinations
Under ordinary conditions, laboratory examination of blood evidence can determine the
following characteristics about the source of the blood:
• Species (human, dog, horse, and so on).
XIII. Cosmetics Applicators and DNA
In missing and unidentified remains cases, obtaining a DNA sample may be crucial. Cosmetic
applicators can be a potential source, including eyeliner smudges, pencils, eye shadow sponges,
XIV. Firearms
Firearm evidence is commonly encountered and includes single- and double-action revolvers,
Investigators must acquire a broad, working knowledge of firearm evidence for three primary
reasons:
• The frequency with which they will encounter it.
• One’s personal safety and that of others.
• The value of such knowledge in a gunfight situation.
A. Laboratory Determinations
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Laboratory examinations may be able to make the following determinations:
• Was this bullet fired from this weapon?
o Shotguns are smooth-bore weapons, but pistols and rifles have rifling. The
• What else can be learned about the bullet?
o A fired bullet yields evidence of the class characteristics of the weapon that fired
• What determinations can be made from cartridge case?
o In contrast to a bullet, which is typically acted on only by the barrel, a cartridge
case is subject to a number of different forces that make marks on it, any of which
can produce individual-characteristic evidence.
• What miscellaneous determinations can be made by the examination of firearms
evidence?
o Has the firearm been modified to discharge in a manner other than designed, for
example, for automatic firing?
B. Collecting Firearm Evidence
A cardinal rule in handling weapons at the scene of a crime is that they should never be
picked up or moved until they have been photographed and measurements have been made
for the crime scene sketch. As in the case of many rules for criminal investigations and as
discussed in an earlier chapter, there are several exceptions:
• If rapidly deteriorating weather conditions, for instance, a driving rain/sleet/snow storm
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potential danger of falling and discharging.
Following documentation, the process of collecting firearms evidence includes:
• Noting the position of the hammer and the slide, and safety, if applicable.
• Recording the description of rounds and empty chambers in a revolver.
• Removing cartridges from a revolver and packaging them individually.
In no case should a pencil or similar object be placed into the barrel of the gun to pick it up;
this can dislodge evidence that may be in the barrel, such as tissue, blood, hair, or other trace
evidence, and it can contaminate the barrel, thereby confusing the laboratory examiner.
To enhance the recovery of blood, tissue, and fingerprints, firearms evidence should be
handled as little as possible consistent with the need to process it and “safe” the firearm.
C. Marking and Packaging Firearm Evidence
The FBI and many state crime laboratories do not recommend marking directly on firearms
evidence. A gun should be tagged and placed in an approved firearms box. Magazines are
XV. Tool Marks
There are three categories of tool marks: (1) impressions, caused by a perpendicular force acting
against an object, for example, a hammer strike; (2) scrapes, produced by an instrument moved
laterally across a surface, such as a prybar (on wood, the same action would create an
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impression); and (3) pinching/shearing actions, created by bolt cutters, cutting pliers, and related
tools.
Tool mark examinations are made to:
• Identify what type of tool made the mark.
• Determine if the tool has evidentiary value.
XVI. Questioned Documents
Loosely defined, a document is anything on which a mark, symbol, or writing is made for the
purpose of transmitting a meaning. A disputed or questioned document is one whose origin or
authenticity is in doubt.
A. Handwriting Samples and Examinations
Handwriting samples may be requested or non-requested. Some state/regional laboratories
provide booklets for collecting requested samples of signatures and extended writings. Non-
B. Laboratory Determinations
In addition to the possibility of determining whether handwriting can be attributed to a
particular person, laboratories may be able to do the following:
• Determine whether a document is authentic or counterfeit. In 1983, 62 volumes of
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1982.
• Recover indented writing; if not visible to the eye, indented writings may be located by
an electrostatic detection apparatus (ESDA).
• Identify the class/type of the writing instrument, such as a ballpoint pen, felt-tip pen, or
pencil.
• Establish the source of paper through watermarks and other features.
• Detect erasures, obliterations, and alterations to documents.
• Determine whether one or more pages in a document were added subsequently to its
original production.
• Establish the relative age of a document.
C. Collecting and Packaging Evidence
In many respects, all evidence collection is like the first rule of physicians: do no harm.
Investigators should not attempt to reassemble torn or shredded documents; write on, trace,
highlight, or underline portions of them; or make repairs to or fold them. Documents should
be collected and processed using the following guidelines:
• Wear gloves and use clean tweezers to handle documents.
• Handle the documents as little as possible.
Chapter 4: Physical Evidence
Swanson: Criminal Investigation, 13e