Friction
ridges contain rows of sweat pores. Sweat mixed with other body oils
and dirt produces fingerprints on smooth surfaces. Fingerprint experts
use powders and chemicals to make such prints visible. The visibility
of a set of prints depends on the surface from which they're lifted;
however, with the help of computer enhancement techniques that can
extrapolate a complete pattern from mere fragments, and laser
technology that can read otherwise invisible markings, fingerprint
experts increasingly can retrieve identifiable prints from most
surfaces.
The age of a set of fingerprints is almost impossible to determine.
Therefore, defendants often try to explain away evidence that their
fingerprints were found at crime scenes by testifying that they were at
the scene and left the prints at a time other than the time of a crime.
How to Achieve Exclusion of 'Known' Fingerprints:
To prove that the defendant's prints are the same as those left at
the crime scene, the prosecution must demonstrate that the known
fingerprints--those rolled prints taken during a booking procedure, for
example--in fact, belong to the defendant. The most common way for this
to be demonstrated is to have the officer who fingerprinted the accused
upon his arrest come to court and testify that he witnessed the taking
of the known fingerprints" preserved on a card, and affirm that they
belong to the defendant. Although you might think that this procedure
is routine, you would be surprised at how often the prosecution's case
gets derailed by its inability to establish this link in the
evidentiary chain.
Challenges to the rolled prints are some of the most effective means
to win an early victory. These challenges can be made via a motion in
limine or via an objection during trial. Either way, counsel should be
prepared before trial with a detailed basis for proposing the exclusion
and supporting authority. The following arguments have been successful
in precluding the prosecution's evidence of the "known prints." Be
aware of the risk that accompanies pre-trial motions: Alerting the
prosecution to the need to cross its "t's" and dot its "i's" before
trial.
Authentication--Attempts to introduce fingerprint cards without
first authenticating them by establishing how they were obtained,
affirmatively showing that they reflect the fingerprints of the
defendant, and obtaining the requisite signatures required within the
jurisdiction can be met with a motion to exclude such evidence from
trial.
Personal Knowledge--Prosecution failure to introduce fingerprint
cards without establishing the personal knowledge of the recording
official--even if the defense fails to object--can be the basis for
exclusion of the known prints. The defense may move to exclude the
cards from evidence on the grounds that the prosecution cannot use such
cards to identify the defendant as the person who left prints at the
crime scene, because there is no one to connect the defendant to the
person represented by the fingerprint cards.
Chain of Custody--If there are breaks in the chain of custody that
make it difficult for the prosecution to demonstrate that the known
fingerprints reflect the identity of the defendant, move in limine for
the known prints to be excluded as hearsay.
Notice of Expert Testimony--Failure to provide notice of witness
testimony can get the prosecution into hot water. If the prosecution
attempts to get the fingerprint cards admitted through the testimony of
an expert, move to exclude them in limine unless the government has
provided notice of the use of an expert witness pursuant to discovery
rules.
Prejudicial Evidence of Prior Arrests--When the "known fingerprints"
are fingerprints taken from a previous arrest, their introduction may
be irrelevant and prejudicial to the defendant by permitting the jury
to infer his prior criminal conduct. If such evidence is going to be
introduced for comparison with the latent prints, move in limine for it
to be excluded.
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