2013 was a record-breaking year for exonerations in the United States, according to statistics compiled by the National Registry of Exonerations.
At least 87 people were set free for crimes they did not commit last year, the highest number since researchers began keeping track more than 20 years ago. Some of those people spent decades in prison before release.
And it's no longer just DNA evidence that's driving exonerations, the registry's report finds. It's because police and prosecutors have been more willing to investigate themselves.
"It's taken a while for people to begin to believe these unfortunate and very distasteful facts," says Samuel Gross, a University of Michigan law professor who edits the registry, a joint project between Michigan and Northwestern University's law school.
"The number of exonerations and the number, in particular, of ones where police officers and prosecutors have initiated the process or cooperated in the process has grown dramatically," he says.
Conviction Integrity Units
Only one-fifth of the exonerations last year relied on newly tested DNA. More than 30 percent occurred because law enforcement agencies reopened a long-closed case or handed over their records to someone else who wanted to take a look.
Gross says that's a sea change from just 10 years ago.
"The sharp, cold shower that DNA gave to the criminal justice system has made us realize that we have to re-examine other cases as well," he says. "That was a serious wake-up call, because that showed we made mistakes in a lot of cases where it never occurred to anybody that a mistake had been made."
Nowhere is this change more visible than in district attorneys' offices across the country. New York, Miami, Chicago, Los Angeles and others have opened "conviction integrity units," with the sole function of reviewing old cases and ensuring that the agency got it right.
But Scott Burns, the executive director of the National District Attorneys Association, takes issue with the idea that prosecutors are more willing to open old cases than before.
"We always did that, we just didn't call them something," Burns says of the conviction integrity units. "We always reviewed big cases, multiple murders or high-profile cases. What you're seeing now is that it's institutionalized it's given a name, probably a line item on a budget in a large office and that's good as well."
Building Public Trust
There are 2,500 district attorneys' offices across the country. Burns says many, if not all, would be happy to have such a unit. But in most cases, it's just not possible. Several hundred of the offices have only one or two prosecutors on staff.
Burns says that while there may be more reviews happening, there is also simply more attention paid to wrongful convictions. He says it rarely makes news when prosecutors willingly test DNA in an old case and it turns out the offender was guilty.
Still, he says being open to examining old cases is good for prosecutors because it builds public trust.
"Anything we can do to ensure the integrity of a conviction is a positive and good thing, and we're for that," Burns says.
That's going to become more important in coming years as the number of exonerations based on DNA evidence decline. These days, if there is DNA to test, it's matched or not matched to a suspect long before anyone sees a courtroom.