Mistakes that let criminals go free [Editorial]

Our view: Reforming the procedures for police lineups and photo arrays should be a priority for lawmakers in Annapolis this year

March 05, 2014

Statistics suggest that every year thousands of people are convicted and sentenced to prison for crimes they didn't commit because witnesses falsely identified them in police lineups or photo arrays. It is a testament to the fallibility and malleability of human memory that witnesses regularly err in recalling what they saw or heard even when convinced the testimony they give is truthful. Too often, it appears, the result is that innocent people end up behind bars while the real perpetrators remain free to commit more crimes.

That is why state Sen. Lisa Gladden and Del. Joseline Pena-Melnyk have introduced legislation in this year's General Assembly to reform the procedures law enforcement agencies in Maryland use to identify criminal suspects. The legislation would require police departments and sheriffs' offices across the state to adopt a set of best practices developed by the International Association of Police Chiefs and the U.S. Department of Justice aimed at reducing the potential for error by witnesses viewing police lineups and photo arrays. The changes proposed in their bills are badly needed both to protect the innocent and to ensure that the guilty are held accountable.

In recent years a growing body of evidence has emerged suggesting that eyewitness testimony, once considered the gold standard of proof in criminal trials, is far less reliable than previously thought. Researchers now suspect that up to a third of the 75,000 witness identifications made in the U.S. annually may be wrong for one reason or another. Moreover, the advent of DNA testing has resulted in the exoneration of nearly 200 people so far who were convicted on the basis of faulty identifications.

How do so many people mistake what they thought they saw or heard in a way that leads to innocent people going to prison? In many cases, the answer seems to be that witnesses are unconsciously responding to subtle cues given off by the officers conducting the lineup or presenting the photo array — officers who may themselves be unaware they are unintentionally communicating which people they suspect committed a crime. Witnesses can also feel pressured to identify someone if only to show they are cooperating with authorities or to end the questioning.

In such cases they may choose a person who looks the most like their memory of the suspect even if that person is not the one they actually saw. Nor are they consciously lying when they do this. Instead, it appears to be more a matter of their conforming their memories to the expectations of the officers and to the context in which they find themselves. Usually they believe absolutely that they are telling the truth to the best of their knowledge and will stick to their story even in the face of overwhelming evidence to the contrary.

The best practices developed by the police chiefs and the Justice Department aim to reduce witnesses' reliance on guesswork and intuition by isolating the identification process from the influence of the officers conducting it. One change would require police to show witnesses pictures of potential suspects one at a time, in sequence, rather that presenting them with groups of images and asking them to pick out the person they saw. That discourages witnesses from comparing all the pictures at once and simply picking out the one that most closely resembles their memory of the suspect.

Another change would require photo arrays to be shown by officers who themselves do not know which images show actual suspects. That prevents them from unconsciously communicating their own suspicions about which, if any, individual may have committed the crime and forces witnesses to make that choice on their own. Currently, only the Baltimore City and Prince George's County police departments employ this "double blind" procedure in police lineups and photo arrays, but because of manpower shortages even they have not established separate units of investigators to carry out the process as recommended by the best practice guidelines.

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