FM - CID Agents Association

FM - CID Agents Association
Chapter 20
Fingerprint evidence remains the most positive means of personal
identification in forensics, to date. Though often compared with other
modern innovations such as DNA, fingerprint evidence results in positive
identifications whereas other evidence does not. Fingerprint evidence can
also distinguish between identical twins. Identifications can be effected
from fingerprints made in a victim's blood, paint, or other contaminants,
which no other form of evidence can accomplish. There should not be
competition between fingerprint evidence and other innovations because
all should work hand in hand to solve identification questions.
20-1. Latent prints can be seen or unseen and often require development. The
word “latent” means “hidden,” but normally the term latent prints refers to
those prints left at crime scenes and/or on items of evidence. Another category
of latent prints is patent prints. Patent prints are impressions that are visible
in some form of contaminant. Plastic prints are those impressions left in
materials, such as wax, window putty, or other pliable materials.
20-2. Record prints are the controlled recordings of the friction ridge skin
contained on the palms of the hands and each finger, using various methods
such as fingerprint cards, printer’s ink, or electronic recording by way of “live
scan.” Though there are many variations on how to obtain record prints, the
principles are the same. Traditionally, the term major case prints refers to
finger and palm prints. Record prints can also be taken from feet, which also
bear friction ridge skin. Record prints must be submitted for all victims,
witnesses, suspects, medical and law enforcement personnel, and anyone
known or suspected of handling evidence or entering a crime scene. Once
legible and complete elimination prints for investigators are on file at
USACIL, there is no requirement to resubmit record prints for each
investigation conducted. In some cases, it may be necessary to record ear and
lip prints for comparison. The laboratory should be contacted for guidance in
these cases.
Fingerprints 20-1
FM 3-19.13
20-3. Prints deposited on items of evidence are generally divided into the
following two basic categories:
Porous evidence. This type of evidence can absorb fingerprint
residue into its surface. Porous evidence can be best described as a
sponge that absorbs residue; for example, paper, checks, currency,
unfinished wood, cardboard, and other similar material. These items
do not require treatment by the crime scene investigators. In fact, the
investigator should not attempt to process fingerprints on porous
items of evidence because laboratory-processing procedures are best
for this type of evidence. Clean gloves should be worn at all times
when handling porous evidence. Little danger exists of destroying
latent prints on porous evidence, but a high possibility does exist of
accidentally depositing additional latents. All porous evidence should
be placed in a paper envelope, bag, box, or wrapped in paper and
sealed. The outside of the container should be marked with unique,
identifiable markings. Investigators should be aware that the
laboratory cautions against the field use of chemical agents
commercially marketed for the development of latent prints on porous
materials. Some of these products are of poor quality and can damage
or destroy latent prints. Latents developed in the field can fade or
totally disappear before laboratory examination. An example is
latents that are developed using iodine and ninhydrin, which produce
“fugitive” prints or prints that fade within a short period of time after
initial development. If an investigator believes that a scene or
evidence could best be processed using such chemicals, he should
consult with USACIL for advice and guidance.
Nonporous evidence. This type of evidence does not readily absorb
water into its surface; for example, plastic bags, painted or sealed
woods, metal, glass, some glossy magazine covers, knives, guns,
computer equipment, and like materials. All nonporous evidence
selected for latent-print examination should be processed as soon as
possible. If ridge detail is visible, photographs should be exposed of
them before any further processing. All nonporous evidence should
then be exposed to superglue fuming. For most evidence, this fuming
process could be all the processing necessary before shipment to the
laboratory. In other circumstances, fumed latents can be
photographed, powdered, and lifted. Do not submit evidence to the
laboratory if the investigator has powdered the latent prints and they
are capable of being lifted. Send only the photographs taken before
lifting and the actual lifts. However, evidence requiring examination
by other divisions of the laboratory should never be processed with
fingerprint powder because contamination can hinder other
examination processes. Evidence requiring additional examination
merely needs to be fumed with superglue as soon as possible.
NOTE: Superglue should not be used on any evidence being
submitted for trace evidence examinations.
20-2 Fingerprints
FM 3-19.13
20-4. Latent prints on nonporous evidence are often deposited on the surface
of an item and are extremely vulnerable. Wearing gloves does not protect the
latent prints from being destroyed if they are touched, rubbed, or smeared;
they only prevent additional prints from being deposited. When it cannot be
determined from appearance whether a drop of water would be absorbed into
a surface, the evidence should be handled and processed as nonporous (such
as a leather wallet, cigarette cartons, and shiny cardboard boxes).
Photography, superglue-fuming, and fingerprint-powdering are techniques
used to preserve latent prints.
20-5. The very first step in latent print preservation is photography. Visible
latent prints should always be photographed to prevent the loss of evidence.
Latent prints deposited in grease, blood, paint, and other visible substances
will often not require additional processing before photography. Always use a
scale in evidence photography and steady the camera using a tripod. It is best
to use a macro lens, filling the entire frame. Do not use digital photographic
field-issued equipment; digital photography has not advanced technologically
for the recording of latent print evidence. Traditional photography is still
required for latent print evidence to be suitable for identification. If there is no
other choice but to use digital photography, use maximum resolution (largest
photo file size) settings combined with good lighting and a tripod.
20-6. Attempt to keep the back of the camera parallel to the surface bearing
the latent print. If it is necessary to photograph the evidence from an angle to
catch the light in a manner that increases the contrast of the latent print,
additional photographs should also be made of the same area with the camera
back parallel to the surface bearing the latent print.
20-7. Superglue fuming, or cyanoacrylate fuming, remains the most effective
way to develop, protect, and preserve latent prints on nonporous evidence.
The superglue-fuming process can be accelerated using heat or chemicals.
USACIL suggests heat to accelerate the fuming process. After the latent
prints are developed, package and ship them to the laboratory. Studies
conducted by USACIL have shown that latent prints on evidence that was
superglue-fumed in the field are preserved better and have a significantly
greater chance of being identified than latent prints not superglue-fumed, but
forwarded to the laboratory as found. Superglue fuming preserves latent print
evidence making it stable for shipment to the laboratory without any further
processing. It can simply be placed in an envelope, bagged, or wrapped in
paper without special packaging materials and shipped to the laboratory.
Superglue-fuming procedures are as follows:
Evidence should be placed in a suitably sized, sealed container and in
an area that is well-ventilated.
A test print should be placed in a container where it can be seen or
checked. A small piece of a clear plastic bag will work.
Fingerprints 20-3
FM 3-19.13
A few drops of liquid superglue should be put on a piece of foil or
laboratory tin and placed on a coffee cup warmer, or a similar heat
source, inside the container.
The evidence should be observed—this is critical. When the test print
has developed, any latent prints on the evidence will also develop.
The evidence should be removed from the container and placed in a
paper envelope, bag, box, or wrapped in paper to be transported to the
20-8. Large items of evidence can be fumed in much the same way. The
investigator may have to build a makeshift tent or enclosure to seal in the
evidence. Latent prints developed with superglue fuming on large or
immovable items of evidence should be dusted with fingerprint powder,
photographed, and lifted. Only the lifts should be sent to the laboratory. This
effort saves shipping and handling costs of large bulky items.
20-9. Caution should always be used to ensure the safety of investigators who
are using this fuming process. Superglue fumes should not be inhaled or
exposed to the investigator's eyes, especially if he is wearing contact lenses
because these situations can create medical illnesses.
20-10. The traditional fingerprint-powdering technique is still a vital piece of
the identification and preservation process of fingerprint evidence. The
preferred method of recovering latent fingerprints from a crime scene
(especially those that are located on large, bulky, or immovable items) is to
superglue fume it first and then powder and lift the latents.
20-11. Many latent prints can be developed and preserved using a fingerprint
brush and powder. All latent prints developed with a brush and powder must
be photographed (with a scale) before lifting. Latent prints found in dust,
grease, blood, or other contaminants should not be processed using fingerprint
powders. Fingerprint powders are supplied in crime scene kits in several
colors. In most instances, the best powders to use are the black or gray
general-purpose powders. Always choose a powder that contrasts best with
the background of the evidence and the color of the lifter used. Fluorescent
powders can be used to develop latent prints on multicolored surfaces. These
powders require the use of an alternate light source or UV light to be able to
photograph. Effective use of these light sources requires training and
experience. They are very costly and can cause health issues. Only long-wave,
UV light should be used; short-wave, UV light is harmful to the eyes and skin.
Anytime UV light is used to develop latent prints, investigators must wear
protective goggles and clothing.
20-12. Many types of fingerprint brushes are used to apply fingerprint
powder. Examples of these brushes are fiberglass, animal hair, and feather
brushes. For overhead work or in situations where it is critical that the brush
elements do not come in contact with the surface, magnetic wands and
20-4 Fingerprints
FM 3-19.13
magnetic powders are used. The procedures for using fingerprint powders are
as follows:
Check the surface first using a test print. Lightly brush an area away
from the subject surface and determine if any latent prints are
present. If none are present, wipe the surface and apply and process a
test print to determine how acceptable the surface is to the fingerprint
powder processing. The investigator can make a test print by wiping
an ungloved finger on his face or neck to collect skin oils. He should
apply his finger to the test surface to deposit a latent fingerprint.
Pour a very small amount of powder out onto a sheet of paper. Never
dip the fingerprint brush into the container, this causes
contamination and spoils the working properties of the powder.
Touch the powder only with the tip of the brush. Shake off any excess
powder and brush the surface using only the very tips of the powderfilled brush. The key to proper print development is to use a small
amount of powder and a delicate touch. Use a twirling method to
ensure that the sides of the bristles are not coming into contact with
the surface and destroying latent prints.
Watch for the latent print to become visible to ensure that it is not
overbrushed. Overbrushing can destroy the print.
Brush following the contour of the ridges and stop when the ridge
detail is developed.
Stop brushing when the ridge detail is complete.
Discard any unused powder; never return contaminated powder to the
20-13. All developed prints should be photographed and then lifted. All lifts
and photographs should be submitted to the laboratory for evaluation,
examination, and comparison. All latent print photographs should include a
scale. Sometimes a second lift of the same area is necessary to achieve the best
possible lift. Superglue-fumed prints can be powdered and lifted many times
without destroying the print; however, latent prints that have not been fixed
using the superglue process can diminish or be destroyed while attempting to
lift them.
20-14. The most common means used to lift latent prints are commercially
produced lifting devices, such as hinge lifters, lifting tapes, rubber and gel
lifters, and various types of liquid lifting mediums. Hinge lifters and
transparent lifting tape have the advantage of presenting the lifted latent
print in its correct perspective. Latent prints on rubber lifters are in a
reversed perspective and must be reversed again using photographic
techniques to properly visualize and compare the latent print. However,
rubber lifters generally work better than hinge lifters. Transparent lifting
tape works better for taking prints from curved or uneven surfaces.
Transparent tapes used in office work, such as cellophane tape, are not
suitable for lifting fingerprints except in dire circumstances. A lift background
that contrasts the color of the powder should always be used. A gel lifter is not
as tacky as hinge, tape, and rubber lifters. It can be used on surfaces that are
Fingerprints 20-5
FM 3-19.13
more fragile where paint might be pulled away with a powdered print and is
excellent for lifting dust prints. Hinge and rubber lifters and lifting tape store
well; gel lifters may require refrigeration.
20-15. A lifter large enough to cover the entire print should always be used.
The plastic cover should be removed from the rubber lifter with care in one
steady movement. Any pause can result in a crease being left on the lifter
surface. The adhesive side of the lifter should be placed to the developed,
powdered print. It should be pressed down evenly and smoothed out over the
surface. If an air pocket is sealed under the surface of the lifter, an attempt
should be made to force it out. Use pressure or a pin to puncture the lifter and
release the air by applying pressure to the bubbled area. The lifter should be
peeled from the surface in one smooth even motion.
20-16. Transparent lifting tape is applied in much the same way as
commercial lifters. One end of the tape should be placed on one side of the
latent print and smoothed out across the surface of the print. Air bubbles
should be worked out using a pin, if necessary, to expel air trapped under the
surface of the tape. The tape should be pulled free with one continuous
motion. The tape should be mounted on materials that contrast the
fingerprint powder used. A black background should be used for gray or white
powders. A white background should be used for black or dark powders.
Commercial mounting cards usually offer the best types of mounting surfaces
and have contrasting surfaces on each side of the card. Lifting tapes can be
used to lift large areas of latent prints by being applied in overlapping strips,
and a rubberized roller can be used to work out air bubbles. All of the strips
should be pulled free from the surface in one continuous motion with all of the
strips connected together. They should be mounted as one connected piece.
20-17. Many types of silicone and liquid lifting materials are available for
lifting latent prints from uneven surfaces, such as appliances, computer
equipment, and vehicle interiors. Most types work by pouring them over the
powdered latent print and removing them after they dry.
20-18. Only trained laboratory personnel should conduct the vast majority of
chemical processing of latent print evidence in an approved laboratory facility;
however, there are some instances where chemical processing can and should
be conducted in the field by trained investigators. USACIL should be
consulted when there is doubt about using chemical processing. The
premature or improper use of chemical processes in the field can result in the
loss and/or damage of latent print evidence. Most chemical processes are
fugitive in nature, meaning that once the latent prints are developed with
chemicals, they will fade and often disappear before the occurrence of proper
photography and comparison of the evidence. One type of processing that may
be used is small particle reagent (SPR). SPR may be more of a physical
process than a chemical process in that the resulting action is physical in
20-19. SPR is used on wet items of nonporous evidence, such as those covered
in moisture or submerged in bodies of reagent. Metallic particles suspended in
water, lodge themselves in the fatty and waxy residue of the latent print after
20-6 Fingerprints
FM 3-19.13
moisture has washed everything else away. SPR is simply applied and then
rinsed away with water. It also works on metal and masonry type surfaces. It
can be photographed and lifted as with powdered prints, after drying. SPR
comes in contrasting colors and UV formulas.
20-20. To classify, analyze, and compare record fingerprints, they must be
complete and clear. It takes practice to obtain suitable record fingerprints and
could take several attempts to obtain suitable prints from a particular
20-21. Both the person being fingerprinted and the person taking the
fingerprints should always sign and date the record fingerprint cards before
the printing process, which will lessen the chances of smearing wet ink. It is
difficult in court to prove the origin of record prints without both signatures.
All blocks on the fingerprint card should be completed before using any ink to
avoid smearing the prints after they have been transferred to a fingerprint
card. The subject should wash and dry his hands thoroughly to remove any
dirt, sweat, or grime. The subject's hands should be examined to ensure that
they are absent of intentional disguises, such as coatings and any disfiguring.
The following equipment is normally required for printing:
FBI Form Federal Document (FD) 249 (Arrest and Institutional
Fingerprint Card).
Fingerprint card holder.
Printer's ink.
Ink roller.
Ink plate.
20-22. Record prints are taken to show the entire friction ridge skin surface of
the fingers, thumbs, and palms. Record fingerprints for submission to the
laboratory should consist of at least two completed FBI fingerprint cards and
a set of fully rolled fingers and fully rolled palm prints to include the web and
side areas of the palms. (See Appendix G.) To prepare for recording the prints,
the fingerprint card should be secured in the holding device. A small dab of
ink should be placed on the inking plate and rolled until a thin, even film
covers the surface. The consistency of the ink should appear almost opaque.
20-23. The motions for inking the finger and recording the finger are the
same. The fingers are rolled from nail edge to nail edge and from
approximately 1/8 inch below the crease of the first joint to as far up as
possible. This area will allow for the recording of all ridge characteristics
required for correct classification of each finger. The finger is rolled through
the ink and then rolled in the corresponding block of the fingerprint card.
When the investigator takes record fingerprints, he should grasp the top of
the subject's hand to ensure that the finger to be printed is extended. The
investigator uses his other hand to hold the finger at the base where it meets
the palm. He tells the subject to look away, relax, and allow him to do all the
rolling. Each finger should be rolled in one continuous and smooth motion.
Fingerprints 20-7
FM 3-19.13
The fingers and thumbs are rolled from awkward to comfortable, meaning
from left nail edge to right nail edge for fingers on the right hand and right
nail edge to left nail edge for fingers on the left hand. This allows the
investigator to work with the anatomic features of the hands without fighting
the natural resistance of the hands. The finger should not be rolled back and
forth on the ink or the card since this will cause over inking, distortion, and
ink lines to appear on the recordings. The pressure should be firm and even.
Pressing too hard causes the furrows (grooves between the ridges) to fill in
with ink. It is important that the investigator ensures the correct finger is
rolled in the designated block.
20-24. The investigator will have to roll each finger in its entirety for cases
being submitted to the laboratory. This means the investigator will have to
use the ink roller to ink each finger separately and then roll that entire finger
from nail edge to nail edge and from the tip where it connects with the palm of
the hand. This will ensure that each joint of each finger is recorded. The tips
of the fingers should also be rolled. They should be rolled from side to side just
above the corresponding finger on the paper used to record the entire fingers.
A separate full-finger card or piece of bond paper must be used.
20-25. After all fingerprint blocks have been completed, the plain or
simultaneous prints at the bottom of the card should be completed. They
verify the order of the rolled record fingerprints and show characteristics that
are sometimes distorted in rolled prints. Simultaneous prints are made on the
card by pressing (not rolling) the four inked fingers onto the card in the
appropriate blocks at a slight angle so they fit the space. The subject should
hold his fingers straight and stiff. His hand should be level with his wrist. His
wrists should be grasped with one hand and the fingers should be pressed
onto the cards with the other hand. Thumbs are recorded by inking each
thumb and pressing it on the appropriate thumb impression block.
20-26. The investigator must obtain record palm prints from a person each
time his record fingerprints are obtained for an investigation, especially if
that case is being submitted to the laboratory. Ink should be applied to the
subject's palms using the ink roller. Using the inking plate would cause ink
lines, created by the edge of the plate, to appear in the record palm print. The
palm print card or a piece of bond paper should be wrapped around a tubular
object. The subject's heel or base of his palm should be placed on the tubular
object and the palm rolled in a pulling motion from the heel of his hand to his
fingertips. The investigator should ensure that he records the entire center
areas of the subject's palms, which will require direct pressure being applied
to the back of his hand. The investigator should also record his web area
(between his thumb and index finger), thenar edge (the edge of his palm on his
thumb side), and knife edge (the side of the palm opposite the thumb side).
Several recordings of each palm should be taken to ensure that all areas are
recorded properly.
20-8 Fingerprints
FM 3-19.13
20-27. Excessive perspiration and dirty hands and equipment may cause
problems when recording prints. The investigator should always start with
clean equipment and clean fingers. When the person whose fingers are being
recorded are wet from perspiration, each finger should be wiped with alcohol,
quickly inked, and rolled onto the fingerprint card. This process should be
followed with each finger. Some people have dry and/or rough hands. Rubbing
them with lanolin, lotions, or creams can often make them soft enough for
clear, unsmudged prints. If the ridges are very worn or fine, alternate
methods must be used to obtain prints, much like the methods for recording
“postmortem records” (see paragraph 20-30). When nothing seems to work,
USACIL should be consulted for suggestions and guidance.
20-28. If the hands and fingers are deformed, normal printing steps cannot be
followed. The ink should be applied directly to the fingers with a spatula or
small roller, and then a square piece of paper should be rotated around the
finger. When an acceptable print has been made, the square is taped to the
proper box of the fingerprint card.
20-29. If there is an extra finger (usually a little finger or a thumb), the
innermost five are printed as usual on the card. The extra digit is then printed
on the reverse of the card. Webbed fingers should be printed as best as
possible in the rolled and plain impressions blocks of the fingerprint card. If a
finger or a fingertip has been amputated, it should be noted in the proper box
(such as AMP, 1st joint, FEB 1993 or TIP AMP).
20-30. Full record finger and palm prints are always obtained from deceased
individuals. The record prints are used to identify the deceased and/or
eliminate them as the source of the latent print evidence. The process of
taking postmortem record finger and palm prints has always been
cumbersome, but it is too important to take lightly. The investigator only has
one opportunity to obtain postmortem prints before the body is interned. This
process must be completed with accuracy and diligence. The key is to prepare
for the process.
20-31. The means used to record the prints depend on the condition of the
fingers and the investigator's ingenuity. For the recently dead, the process is
the same as for live subjects. The process of inking the fingers and using
inking spoons and square paper tabs on the fingers might be used if rigor has
started. When rigor mortis is present, the investigator may have to massage
and straighten the fingers. Breaking rigor requires a certain technique, and
massaging the fingers and hands takes time (about 10 minutes per hand).
Rigor can be broken using finger spoons or by bending the fingers backward
and pressing down on the middle joint of the finger. If the investigator is not
having any success using conventional methods, he should process the fingers
and palms using equipment and other methods.
Fingerprints 20-9
FM 3-19.13
20-32. The following items can be used for processing fingerprints and palm
prints of deceased individuals:
Black or aluminum fingerprint powder.
A fingerprint brush (soft-hair type).
Transparencies made from fingerprint cards without a textured
White case file labels (precut to finger block size and full-length size).
Larger mailing labels for palm prints.
Blank transparencies or document protectors.
A permanent marker.
Extra large ziplock plastic bags.
Latex gloves.
NOTE: The methods for obtaining record prints of deceased
individuals include before and during procedures.
20-33. Before beginning, the investigator should think “safety first”. He
should wear latex gloves when processing deceased individuals. When
finished and before removing his gloves, he should put the postmortem prints
just taken into a ziplock bag and discard the magic marker used to label the
20-34. It is recommended that the body lie out for about an hour before taking
the prints so that the body can adjust to room temperature, lessening the
problems of condensation during recording. The easiest position from which to
take the record prints is to lay the deceased in a prone position (face down)
with the arms stretched out in front of the body.
20-35. The hands of the deceased should be clean and dry. The investigator
may have to use some alcohol swabs to ensure that the skin is dry enough to
receive a light dusting of powder. It may be necessary to massage the fingers
and palms to make them more pliable and receptive to the print-taking
process. This massaging will open up the palm area for better record taking. A
small worktable should be used for laying out the supplies and equipment.
This makes the printing process easier.
20-36. During the printing process, the fingerprint powder should be brushed
on the palm side of the right thumb of the deceased. If the investigator always
starts with the right hand in the following order: thumb, index, middle, ring,
little finger, and then the left hand in the same finger order, it will help him
stay organized and keep him from making mistakes with labeling. He should
place a precut, white case file label on the tip of the finger and gently smooth
out the label, molding it to the finger. He should use the same process until
the complete fingerprint card is full. The larger labels should be used to
complete the simultaneous prints.
20-37. To obtain full record fingerprints, the entire finger should be powdered
from tip to base (where the finger joins the palm) and from nail edge to nail
20-10 Fingerprints
FM 3-19.13
edge. Again, the investigator should gently and steadily peel the label from
the finger and attach it to the back of the blank transparency. He should
immediately write on the front of the transparency just below the applied
label which finger it is so as not to lose track or get the labels out of order. The
investigator should remember that, when viewing the ridge detail through the
transparency, it is a reversal of the pattern on the actual finger. The following
includes methods for obtaining fingertip prints, palm prints, and guidance for
special cases:
Fingertips. The tip of the finger can be powdered and a label applied
across the tip from side to side. This process should ensure that all of
the ridge detail available has been captured. The recorded tip should
be placed just above the corresponding finger on the blank
transparency. The investigator should remember to keep all the labels
for the same finger together on a transparency and label each
accordingly. These same steps should be repeated for all ten fingers.
Palm prints. The investigator should use the same method for taking
palm prints as he did for taking fingerprints, but this time he should
use the larger mailing labels. In most cases, the investigator will have
to overlap two labels in order to obtain all the ridge detail on the
palms. The investigator should remember to keep those two labels
together when removing them from the hand and applying them to the
back of the transparency. He should gently mold the labels to cover
the center of the palms, the edges of each palm, both the little finger
and thumb sides, the area where the wrist connects to the forearm
(the wrist bracelet area), and the interdigital area where the palm
connects to the fingers.
NOTE: In some cases where fingers and/or palms are too damaged
to allow for the powdering of the skin, photography or other
methods may have to be applied.
Special cases. The hardest record prints to obtain are those from a
body that has started to decompose. It may require techniques beyond
the investigator's expertise. When the hands are badly damaged, the
investigator may need to coordinate with USACIL for guidance on
how to proceed.
Fingerprints 20-11
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