During a criminal investigation, law enforcement agencies in Minneapolis make it a point to look for eyewitnesses. Victims of sex crimes and other violent acts are asked to identify their attacker from a police lineup or a collection of photographs. However, while the use of eyewitnesses is commonly accepted, their reliability has come into question.
Last year a report was written by the National Institute of Justice. The report stated that since 1989, DNA testing has led to the release of more than 300 people who were convicted of a crime they did not commit. Out of that number it was revealed that 75 percent of all wrongful convictions were attributed to eyewitness testimony error.
System variables
Part of the problem appears to be related to the lack of standard policy in law enforcement agencies. When it comes to photo identification, less than 40 percent of agencies have a formal standard for handling the process. Lineup identification showed fewer than 20 percent of all agencies with a written policy on how the identification should be conducted.
The New Jersey Supreme Court identified problems like this as system variables and points out that lineup identification often results with the wrong person being chosen as the perpetrator. Sometimes law enforcement can inadvertently influence an eyewitness in their choice through officers’ comments or applying pressure on the witness.
In Oregon, a woman told nurses that she did not see the person who shot her and her husband at a campsite. Yet, when detectives focused on a man whom the woman had met earlier on the day of her husband’s murder, she testified in court that she saw him shoot her husband. The man convicted of the murder, filed an appeal and the state’s Supreme Court agreed that law enforcement had influenced the woman’s identification. The high court overturned his conviction and ordered a new trial.
Estimator variables
In addition to system variables, there are estimator variables and these are external factors that can influence a person’s identification of a suspect. These factors include:
- Environmental lighting
- The presence of a weapon – studies show that people focus more on the weapon than the person holding it.
- The person’s emotional and psychological stress level
- Distance between the witness and the perpetrator
- The natural decay of memory
It is also not uncommon for people to identify someone that they encountered briefly, prior to the event, as the perpetrator, especially if they are the victim of the crime.
The fact that hundreds of people have been wrongly convicted in the U.S., because of faulty testimony, should serve as a warning for Minnesota judges and juries in accepting a person’s eyewitness account. The purpose of the U.S. justice system is to ensure that innocent people are not sent to prison but the common acceptance of eyewitness testimony has resulted in the opposite.
