One thing that struck me about the saga of the serial stabber was the contrast between the sketch of the suspect, and the actual suspect that was captured.

I, for one, would not have identified the man on the right with the sketch on the left. Clearly, the eyewitness information provided was insufficient to catch this creep, and hard, focused police work proved decisive.

And yet, a huge number of people are convicted of crimes on the basis of eyewitness testimony alone. Follow below for a discussion of the dangers and implications of relying on eyewitness testimony.

The DNA revolution that began in the late 1980s has dramatically demonstrated how utterly unreliable eyewitness identifications are. About 200 people convicted of violent crimes have been exonerated by DNA evidence in the past two decades. About 80 percent have been the victims of eyewitness misidentification. Some of them served even more time in prison than Tillman.

Even more disturbing are the results of the FBI’s DNA analysis of biological specimens in 10,000 cases from 1989 to 1996.

These were all cases in which eyewitnesses had identified a suspect who had been arrested for the crime (usually sexual assault) and biological material from the perpetrator was available for comparison with the suspect’s. In 20 percent of the cases, no conclusive results could be obtained. In the remaining 8,000 cases, however, the suspect was cleared in 2,000, or 25 percent. Assuming that without DNA evidence half of these defendants would have been convicted, then as many as 12 percent of those convicted in disputed eyewitness cases may be innocent.

At least 80,000 prosecutions in this country every year rely largely on eyewitness testimony. If only half of those result in convictions, we may still be sending to prison nearly 5,000 innocents annually, based on false eyewitness testimony alone. – Yale Law School

Eyewitness testimony is notoriously unreliable, as has been documented by a wide range of scientific studies. This is why the DNA revolution has been so critical to our criminal justice system. It is also why it is critically important that we maintain funding for cops and detectives even as we look for ways to save in our local government budgets. We want our cases against criminals to be as solid as possible, and not rely on eyewitness testimony alone.

Here in Virginia, felony convictions have enormous consequences as the convicts typically have their right to vote stripped for life, in addition to they stigma and job opportunity penalties that accrue from such a conviction. After conviction, the US justice system often hands out punishments that far outweigh the crimes. This is all the more reason that when it comes to criminal convictions, we need to get it done right, rather than get it done fast.