The Innocence Project, established by lawyers Barry Scheck and Peter Neufeld, began in 1991 as a clinic for students at Yeshiva University's Benjamin N Cardozo School of Law.

Prisoners who maintain their innocence write to the Project through their lawyers, and students in the law school assess each case brought to them. These cases are screened using the clinic's criteria. Questions include: was identity one of the key issues when the case was originally tried? Was biological evidence taken¹?

The next problem is gaining access to the biological evidence, which is often in the possession of the same prosecutors who gained the conviction. Certain they have their man (or woman), these prosecutors will likely not be hard-pressed to cooperate - even though roughly 60% of the samples tested exonerate the clinic's client.

As time passes, however, there will be fewer cases suitable for the Innocence Project. Most of its cases are old ones, prosecuted before DNA testing was common or even available. But the question still remains, why is the justice system making so many mistakes?

One answer is that juries will often convict on astonishingly little evidence. For instance, one exonerated client, Dennis Fritz, was convicted despite there being no evidence linking him to the crime scene. He spent 12 years in prison. And in the case of Tim Durham, the jury ignored 11 alibi witnesses! Durham served six years of his 3220-year sentence before being released. One final problem is that - contrary to popular belief - eyewitness testimony is less than reliable. One reason, it turns out, is that people can have trouble distinguishing between two individuals in an ethnic group other than their own.

But the Innocence Project is helping. Since 1992, 70 prisoners have been released thanks to the Innocence Project - eight of whom were on death row. With any luck, they'll continue changing lives for years to come.