Criminal cases in Illinois sometimes depend on testimony from witnesses. Although people tend to believe witnesses who identify suspects, this information is potentially unreliable. The Innocence Project, which helps people wrongfully convicted of killings and sex crimes gain their release with DNA evidence, reported that 71 percent of 350 exoneration cases involved witnesses who had identified the wrong people. A reform, known as a double-blind lineup, has begun to take hold in the law enforcement community because the new approach reduces the possibility of people misidentifying suspects.
Witnesses often take their cues from the body language of police investigators when they view a lineup of suspects or photographs. Police who have their suspicions about a specific person might encourage a witness to select that person. In a double-blind lineup, the person conducting the session will not have knowledge of who the suspect is. This will eliminate the chance of a witness being led to make a certain choice. An investigator should also tell a witness that the suspect might not even be present. This way a witness might not feel pressure to pick someone despite uncertainty.
Research about the limits of memory also undermines the notion that witness identifications are infallible. For decades, university researchers showed that people’s memories do not produce perfect recordings of events.
An evaluation of witness testimony might be part of the services that a criminal defense attorney performs for a person facing criminal charges. An attorney may look at the evidence and question its validity or association with the person. This effort might weaken the case and result in a case dismissal, lenient plea deal or acquittal. Advice from an attorney may also help a person make the decision between going to trial or accepting a plea bargain.