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Suspect Identification
Chapter 17
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Overview
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Fingerprints
Voice Identification
Linguistics Identification
Eyewitness Identification
Review Questions
Opportunity for Student Questions
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Learning Objectives
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Explain the importance of suspect identification to the
overall task of criminal investigation
Define the three basic patterns of fingerprints
Discuss the different types of latent fingerprints that may
be encountered at a crime scene
Understand the mechanics of processing, developing, and
lifting latent fingerprints
Understand the computerized fingerprint identification
technique
Explain the technique and function of voice identification
Discuss the major categories and significance of
eyewitness identification
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Suspect Identification
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A primary task of the investigator is to
identify the perpetrator
Many of the cases that are referred to the
investigator are of the unknown-suspect
category
If the suspect's identify is known,
identification procedures may be required
to confirm information
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Identifying the Suspect
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There are two basic types of suspect
identification
– Positive identification
Includes fingerprints and DNA
 Legally conclusive
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– Tracing identification
Tends to incriminate the suspect
 Includes shoe impressions, vehicle
descriptions, general physical descriptors
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Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Fingerprints
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Fingerprints can be classified into three basic
patterns:
– Loop
– Whorl
– Arch
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There are five terms that are associated with
fingerprints:
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Pattern area
Type lines
Divergence
Delta
Core
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
The Three Main Patterns
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Latent Fingerprints
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Latent fingerprints are ridge impressions
that are found at a crime scene
They are invisible until some material
renders them visible
They are often of great importance in an
investigation
No other crime scene evidence is accepted
so readily in the courtroom as are
fingerprints
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Visible and Plastic
Fingerprints
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Visible fingerprints
– As the name implies, can be seen without the use of a
developing material
– Usually due to the transfer of existing materials from the
fingertip to the surface of the object–typically caused by
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Dirt
Blood
Plastic impressions
– May result when the fingertip comes in contact with a soft,
impressionable material leaving prints on such things as:
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Wax
Soap
Grease
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Locating Latent
Impressions
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Protect the crime scene upon arrival to
avoid loss of prints (or adding of nonsuspect prints)
All police personnel present should wear
gloves and no one should touch anything
Check areas pertinent to the crime scene
Reconstruct the actions of the suspect
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Examples of Where Latent
Prints May Be Found
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Objects of attack (safes, drawers, cash registers)
Point of entry and exit
Pathway to the object of attack
Anything that the suspect would have had to touch
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Controls of the vehicle
Handles
Door knobs
Weapons
Receipts, checks, and other paper
Pens
Bullets found inside the magazine, chamber, or cylinder
Light switches
Drinking glasses
Debris such as discarded cigarette packages, butts, fast food wrappers
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Developing Latent
Impressions
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When visible, plastic, or latent fingerprints are located:
– Photograph the item (overall) first that has the print on it
– Then photograph the fingerprint itself (scaled and unscaled)
using a 1:1 fingerprint camera or a camera that allows 1:1 or
macro setting to clearly show the minutiae
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Latent prints are developed (on non-porous surfaces)
by several methods
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Dusting the surface is the most common
Spraying
Alternative light sources
Fluorescent powders
Superglue fuming
Small particle reagent (for submerged items in found in water)
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Developing Latent Prints on
Porous Materials
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Prints may be found on paper, cardboard, and other
porous materials
Several chemical methods may be used to produce
readable prints
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Iodine fuming
Ninhydrin
Silver nitrate
DFO
These methods may produce the prints only temporarily
and some prints are quite fragile
Requires immediate photography
– 1:1 photos if possible or scaled and unscaled pictures
– Ensure the film plane is parallel to surface
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Computerized Fingerprint
Processing and Identification
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Automated Fingerprint Identification Systems (AFIS)
– Computerized data base of offender prints
– Hundreds of thousands of prints are stored and compared
within minutes
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Live-scan fingerprinting process allows police to place a
suspect’s fingers on a glass plate for recording (no ink)
– The prints are ‘read’
– Produces a digital image of the prints
– The image can be transmitted to a main AFIS computer
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Compared for outstanding warrants
Look for the criminal history of the suspect (previous arrests and
convictions)
Confirm the identity of the person arrested
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Elimination Prints
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If fingerprints are located at a crime scene, elimination
prints must be taken
Elimination prints are full Ten-Print cards taken from
anyone who had legitimate (legal) contact with the area
or item–typically includes:
– The owner
– A friend of the family
– Family members
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This process prevents the AFIS system from storing
legitimate prints in the system looking for future
matches against newly entered arrested persons who
are added to the system daily
Save valuable time and effort
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Voice Identification
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The identification of a suspect based on the hearing
of voice is likely to be legally challenged
The only LEGALLY acceptable method is voiceprint
or spectrograph
– Consists of the identification and/or elimination of suspect
by both
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Aural comparison of voices with a known voice
Visual comparison of voices with a known voice
This is a useful method if the suspect’s voice has
been recorded and a comparison recording is
available
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Linguistics Identification
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Linguistics is the scientific study of language
Linguistic interpretations can assist the
investigator in three forms of analysis
1. Author/speaker comparison
2. Author/speaker assessment
3. Discourse analysis
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All three areas above focus on:
– Language usage
– Comparison methodology
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Linguistics–What is
Actually Compared?
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The evidence is compared to other known samples
of the suspect
Examples include:
Threatening letter compared with letters found on the
suspect’s computers
The recording on the 911 tape with home movie recordings
obtained during a search warrant
What is compared by the experts:
Vocabulary
Syntax
Phraseology
Spelling
The rate of speech
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Linguistics Usefulness
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What can be determined by linguistics?
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Speaker or writer’s age, sex, education
Occupation
Ethnic background
Regional origin
Potential to determine a suspect's level of threat
Actual risk of the crime being carried out
If a rape or stalking victim is making false allegations
Can the science be used in court?
– Depends upon the jurisdiction
– Judge will determine the usefulness to the jury
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Eyewitness Identification
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Eyewitness descriptions furnished by victims
and witnesses are of questionable accuracy
The perception of an event is affected by:
– Internal factors (fear, prejudice, emotions)
– External factors (weather, lighting, distance)
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Investigators must ensure that they are not
suggestive when interviewing victims and
witnesses
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Verbal Statements from Victims and
Eyewitnesses Leading Suspect Identification
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Separate all witnesses
Victims or eyewitnesses should be asked to provide a
description of the suspect
Obtain the following information:
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Name of the suspect (include street names and nicknames)
Race
Sex
Age
Height and weight
Color of hair and eyes
Complexion
Miscellaneous data such as facial hair, limps, teeth, tattoos
Clothing
Objects worn or carried
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Composite Sketches are
Valuable Tools
• The purpose of the composite sketch is
to develop leads (suspect leads) when
the suspect is unknown to the victim,
witness, and the police
• Determine if the victim or witness is
capable of providing the necessary
information to complete a composite
sketch
• Can be released to the media
• Can be forwarded to police agencies
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Computerized Composites
Now, with
computers,
operators
without artistic
ability can
draw realistic
composite
sketches
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Also Obtain the Following
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Exact words spoken
Gestures
Direction traveled
Time (of incident, last seen)
When, if ever the suspect was previously seen
Vehicle information (CYMBAL)
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Color
Year
Make and Model
Body Style
All other information (such as damage, decals, antennas, etc.)
License number
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
In-the-Field
Identification
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Must be done properly to avoid constitutional issues
Return the suspect to the crime scene (for victim/witness
identification) only if:
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The suspect is apprehended shortly after the offense
A formal complaint, warrant, or indictment, has not been issued
Counsel has not been appointed to represent the suspect
Police officers make no suggestions, by speech or action, that the
individual is suspected of any wrongdoing
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Lineup Identification
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The U.S. Supreme Court has issued several
requirements
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A reasonable number of participants
Fillers must be similar to the suspect in age, race, build, sex
Randomly place the suspect in the lineup
The witness should never be told which individual is suspected
The witness should identify the suspect by number
Keep photographs of the lineup
Document the lineup procedure
The suspect has no legal right to refuse a lineup
It is a good policy that the officer in charge of the lineup be unfamiliar with the suspect (double-blind) so no
inadvertent clues are given to the victim or witness
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Photograph Identification
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When the suspect is not in custody, it is common for
the police to conduct a photo lineup
The procedure must be fair (as in the lineup
procedure–the suspect must be similar to the fillers)
An officer who is not familiar with the case and suspect
should conduct the photo lineup (double-blind)
Only show one photo at a time
Inform the witness that the suspect may not be in the
group of pictures
If an identification is made, ask the witness how sure
he/she is and document the witness statement
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Review Questions
1.
2.
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6.
7.
Explain the importance of suspect identification to the overall task
of criminal investigation.
List the three basic patterns of fingerprints.
Discuss the types of latent fingerprints that may be encountered
at a crime scene.
Explain the use of linguistics to aid in the identification of
suspects.
List five suspect descriptors an investigator should obtain from an
eyewitness when obtaining a verbal statement.
What is the AFIS system?
What procedures must be used when conducting photographic
lineups to avoid constitutional issues?
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458
Student Questions
Criminal Investigation, 7th Edition
By James N. Gilbert
PRENTICE HALL
©2007 Pearson Education, Inc.
Upper Saddle River, NJ 07458