For more than two decades, the Innocence Project has used DNA evidence to free the wrongfully convicted.
DNA is the "gold standard" for going back into old cases to prove where things went wrong, said Paul Cates, spokesman for the New York-based Innocence Project. "DNA exposes the cracks in the system in a way it hadn't been exposed before."
Since 1989, 330 people have been released from prison after DNA evidence showed they weren't connected to the crime. The Innocence Project has worked on 176 of those cases.
"To the best of our knowledge, those people are innocent," Cates said.
At a glance:
• The first DNA exoneration took place in 1989.
• Of 330 people who've been exonerated through DNA, 20 served time on death row. Another 16 were charged with capital crimes but not sentenced to death.
• Thirty-one of those exonerated pleaded guilty to crimes they didn't commit.