Transcript Document

Chapter 16
The Crime scene
 Chain of Custody
 Fingerprints and Trace Evidence

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Obtaining evidence from a crime
scene


When a crime occurs in a private premise
such as a home, apartment, office, or
factory, law enforcement officers most
often enter with the consent of family and
victims.
Law enforcement officers may stay in a
crime scene for a reasonable period of
time to perform whatever tasks they are
obligated to do.
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What can police search for in premises where
a serious crime has recently occurred?

The court held in Mincey that law
enforcement officers may make
“warrantless entries and searches
when they reasonably believe that a
person within is in need of
immediate aid” (emergency
situations)
 Law officers “may make a prompt
warrantless search of the area to
see if there are other victims or if a
killer is still on the premises”
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What can police search for in
premises where a serious crime has
recently occurred cont….
The
police “may seize
any evidence that is in
plain view during the
course of their
legitimate emergency
activities”
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Protecting and Searching a Crime
Scene
 The first officer to arrive at the
scene of the crime automatically
incurs the serious and critical
responsibility of securing the crime
scene from unauthorized
intrusions
 To prove that evidence is genuine
and authentic and to show that the
object is what is claimed to be, a
witness would have to be able to:
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
Testify about where and how the object
was obtained
 Identify the object by a serial number if
a serial number is on the object
 Identify the object based upon personal
knowledge and observations
 “If the evidence is not readily
identifiable or is susceptible to
alteration by tampering, substitution, or
contamination, the party must establish
a chain of custody.”
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The Chain of Custody
Requirement


To use physical evidence in a criminal or
civil trail, the party offering the evidence
has the burden of proving that the
evidence is genuine and authentic.
If the evidence (such as fingerprints or
illegal drugs) could be subject to
alteration by tampering, substitution pr
contamination, a chain of custody
must be shown.
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The Chain of Custody
Requirement cont….
 Chain of Custody: all persons who
had possessions of the evidence
must appear as witnesses to testify
that the fingerprints or illegal drugs
had not been tampered with,
substituted or contaminated while
the witness had custody and control
of the evidence.
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Situations not requiring a chain of
custody

A chain of custody is not required if
the object to be used as evidence is
not subject to alteration by
tampering, substitution, or
contamination.
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The following cases are examples:
A
chain of custody is not required
in most shoplifting cases.
A pistol was held to be admissible
without showing a chain of custody.
 Twenty-two silver dollars stolen from a
pawn shop were admitted for use in
evidence although the victim couldn’t
specifically identify them.

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Fingerprints as Evidence
 Latent fingerprints: Prints that are
not visible, that are “processed” and
then taken from a crime scene can
then be compared with fingerprints
on file in local, state, or FBI files.
 Fingerprints are perhaps the most
common form of physical evidence,
and certainly one of the most
valuable. They relate directly to the
ultimate objective of every criminal
investigation: the identification of
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Obtaining fingerprints

Persons in a lawful police custody
are routinely fingerprinted and
photographed. Persons who have
served in the military have their
fingerprints on file as do many
government employees and people
who receive licenses for such
occupations as bartending driving a
taxicab, working in private security
etc.
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Proving that fingerprints were
impressed at the time of the crime
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Fingerprints are circumstantial evidence
from which inferences must be drawn.
It is impossible to determine how old a
print is or when it was originally made.
As a general rule the prosecution must
first introduce fingerprint evidence by use
of an expert witness and show a chain of
custody to prove that the evidence is
authentic, genuine, and has not been
tampered with.
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Proving that fingerprints were
impressed at the time of the crime

To prove that fingerprints were
impressed at the time of the
crime, the following evidence
could be used:
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
The following hypothetical situation illustrates
the potential for the exchange of physical
evidence during a series of fairly typical
criminal actions.
Testimony of the victim or a witness
that the defendant touched or handled
the object on which the fingerprints
were found.
 Testimony that the surface had been
washed or cleaned just prior to the
crime
 Fingerprints found in a home or an area
to which the defendant did not have
access to.
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
Trace evidence: The smallest things
can make the biggest difference.
 Trace
evidence: most often
applied to minute or
microscopic bits of materials
that are not immediately
apparent to even a trained
investigator.
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 Criminal
crosses back
porch steps on brown
paper bag.
 Criminal breaks a small
glass pane on the back
door.
 Struggles with
homeowner.
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Examples of some other types of
evidence
 Palm
prints and lip
prints
 Footprints and shoe
prints
 Bite marks
 Tire tracks
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