We have previously written about the high number of wrongful convictions which have been overturned recently by advancements in DNA testing. Wisconsin’s efforts to update its criminal DNA database should hopefully continue to reduce and rectify wrongful convictions. Most of these wrongful convictions were based on faulty eyewitness testimony.

A recent criminology study shows that the method used by police to show photographic arrays to eyewitnesses can increase the number of false identifications. In cases of rape or sexual assault, or even murder, this may result in innocent persons being wrongfully identified and convicted.

Eyewitness testimony is already notoriously unreliable, but it can actually be even less accurate if police present pictures of all suspects simultaneously. If police instead show eyewitnesses a series of photographs one at a time, the accuracy of identifications is somewhat improved.

When eyewitnesses were shown a group of photographs all at once, they identified a known-innocent person approximately 18 percent of the time, picking out a person whom police just used to fill out the lineup.

When the photographs were shown to the eyewitnesses one at a time, accuracy of identifications increased somewhat because witnesses were forced to compare each picture to the mental image in their mind. However, the eyewitnesses still picked out the photo of the known-innocent person 12 percent of the time.

Given the number of criminal investigations carried out by law enforcement, these frightening statistics could translate into thousands of individuals annually facing the nightmare of false accusations. With offenses such as rape or sexual assault, even exoneration in court may not be enough to wipe the blemish from the reputation of the falsely accused.

Source: Thomson Reuters Westlaw News, “Study finds crime witness ID method can affect error rate,” Kay Henderson, Sept. 19, 2011

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