Eyewitnesses are often used in investigations but science and new evidence points out that they are often inaccurate. Eyewitness testimony is often considered one of the most powerful forms of evidence that can be used in a criminal case. There is nothing more damaging than for a jury in New York to hear a rape victim point out that the person sitting in the defendant’s chair is the person who committed the crime. Yet, eyewitness testimony has come under a great deal of scrutiny lately as new studies and evidence surfaces that rebuts the accuracy of witnesses in recounting events or even identifying the alleged perpetrator.
How accurate are eyewitnesses?According to the Innocence Project, eyewitnesses frequently make mistakes. The organization has successfully helped overturn over 300 convictions through the use of DNA testing and in 70 percent of those cases, eyewitness testimony played a role. To date, 29 people in New York have been exonerated. One of those men was convicted of a dual rape and served almost 25 years in prison before a DNA test eliminated him as the perpetrator. During a police lineup, he was identified by both victims.
Are there factors that can influence a witness’s memory?The American Bar Association points out that witnesses can be influenced by system variables and by non-system variables. System variables are those that are under the control of law enforcement. These include the processes used to conduct a lineup or a photo identification. For example, if law enforcement shows a witness a set of photos and one photo differs in terms of size, coloring or backdrop, the witness will unconsciously be drawn to that photo. Additionally, if officers who conduct the identification process are involved in the criminal investigation, they may give unintentional cues to the witness as to who the primary suspect is. Non-system variables often have to do with the witness and the crime scene. These include the following:
- The presence of a weapon
- Personal prejudices of the witness
- Distance from the perpetrator