Walking through any casino in Las Vegas, you are likely to see hundreds of faces. Unless there is someone you recognize, those faces likely pass out of your memory quickly. If you tried to recall the face of someone who you had never seen before and saw only briefly several days ago, you would likely be hard pressed to identify the correct person.

While it is not surprising that you would not recognize a strangers face several days later, in criminal defense trials this sort of identification by witnesses often makes up a large portion of the evidence used to secure a conviction. In many cases, the witness, though they believe they have a clear memory of the incident, incorrectly identifies a suspect as being the individual that committed the crime.

In one recent case a witness said that she would never forget the face of the man that pulled the trigger shooting a retired police officer. But when put before a police lineup that witness actually identified one of the jurors as the person who committed the crime. But despite this mistake the suspect was convicted and sentenced to prison for 25 years to life. Another witness in that same case described the perpetrator as black man with braids, but during the lineup identified a Hispanic man with short hair as the shooter.

With the advent of the use of DNA evidence in criminal cases the justice system is only beginning to get a sense of the scope of witness misidentifications. An organization called The Innocence Project has used DNA evidence to exonerate almost 300 people who had apparently been wrongly convicted. According to reports, about 75 percent of those exonerated by DNA evidence had been convicted based primarily on identification by a witness.

Source: MSNBC, "Witness error: How mind tricks can put the innocent behind bars," Miranda Leitsinger, Feb. 12, 2012