The outcome of a criminal case often depends on eyewitness identification
of the defendant. During the investigation of a
violent crime, Texas law enforcement officers often conduct live and photo lineups in
which an eyewitness is asked to identify the perpetrator out of a group.
Unfortunately, eyewitness identifications of suspects are notoriously
The problem is a serious one. According to the Innocence Project, a national
organization which seeks to free the wrongly convicted, mistaken eyewitness
identifications were a factor in over three-fourths of the initial group
of 130 wrongful convictions that were later set aside after DNA testing.
According to one researcher, law enforcement personnel need to understand
that eyewitness testimony can be contaminated in the same way as physical
evidence. Research into the subject has led to some recommendations to
reform police procedures. For example, researchers learned that when eyewitnesses
are asked to pick the perpetrator out of a group of photos presented all
at once, the eyewitnesses tend to compare the photos with each other rather
than with their memory. As a result, the recommended practice is now to
show the photos sequentially.
Another recommendation is the use of so-called "double-blind"
lineups, in which neither the eyewitness nor the officer presenting the
lineup knows which person in the lineup is the suspect. This prevents
the officer from intentionally or unintentionally influencing the witness's decision.
Whether a mistaken identification is the result of unintentional bias or
bad behavior by police, an aggressive defense approach may persuade the
judge and jury that the lineup evidence is unreliable. Successfully challenging
a police lineup before trial can even lead to dismissal of the charges.
Source: American Psychological Association, "How reliable is eyewitness testimony?" Zak Stambor, Accessed May 15, 2015