Yell at me. C’mon, yell at me.

As I sat across from Robert Dewey in the Limon Correctional Facility, a maximum-security prison in Colorado, I mentally implored him to convince me of his innocence. He was, after all, serving a life sentence following his 1996 conviction for raping and murdering a 19-year-old woman in Palisade, Colo., but had always maintained that he was not responsible. I needed him to tell me more than "I didn’t do it."

Pound the table. Kick the table. Heck, turn the table over. Be enraged.

He was far from enraged. He was a picture of serenity.

At the time, I couldn’t understand how he could be so composed. He had filed motion after motion asserting his innocence, and up until that moment in early 2011, no one from law enforcement had listened. I was there to listen, and I could help him. But I expected him to be more than a steady voice and nonchalant shrug.

Now, though, I understand why he wasn’t emotional. To survive every day, every hour, every minute, every second of being wrongfully incarcerated, he had to be that stoic. He was preserving his sanity.

I did not investigate or prosecute the original case against Dewey. I lead the Colorado Justice Review Project, a program in the Colorado Attorney General’s Office funded by the National Institute of Justice that looks to identify individuals convicted of violent felonies for whom DNA testing could potentially establish factual innocence. Of all the organizations working on DNA exonerations (such as the Innocence Project), we are one of the few prosecution-based programs in the nation.

Following that afternoon with Dewey at Limon, I was convinced that I needed to look further into his case. With the cooperation of all those involved, my investigator and I reviewed the prosecution, defense, court and laboratory files. We met with Dewey’s current attorney and the prosecutors and defense attorneys from his trial. We spoke to forensic scientists, law enforcement witnesses and lay witnesses. We were not persuaded of his guilt.

Science stepped in to elucidate things. The Colorado Bureau of Investigation conducted DNA testing on the physical evidence in Dewey’s case. The results were nothing short of astonishing — not only for what we learned, but also because we learned it from evidence that was more than 17 years old and had been submerged on the victim in a bathtub full of water. The DNA from the evidence matched a male profile, but that profile was not Dewey’s.

Promptly upon receiving those test res­ults, the Mesa County District Attorney’s Office in Grand Junction, where the case originated, initiated a full-fledged re-investigation of the crime. And, within months, the district attorney and Dewey’s lawyer filed a joint request to vacate his conviction. Dewey was released from custody on April 30, 2012.

Since Dewey’s exoneration, I am often asked why a prosecutor is doing defense work. I am not, I explain. This type of work is wholly consistent with every prosecutor’s responsibility to do justice. All steps before, during and after a criminal prosecution should be cross-checked for truth.

I am not alone in undertaking this type of post-conviction work. Some prosecutors have been doing it for years; others are embracing it relatively recently. Whether prosecutors act singly or through a conviction integrity unit, this appears to be a trend, and should not be overlooked.

The National Registry of Exonerations on April 3 released "2012 Update," a report revealing that prosecutors or police initiated or cooperated in 54 percent of the 63 exonerations in 2012 — a record high and significantly more than the 28 percent of cases in which they were involved between 1989 and 2011.

The involvement of law enforcement in exoneration work is only going to increase. Prosecutors’ offices nationwide are establishing conviction integrity units and instituting best practices to avoid wrongful convictions in the first place. Judging from my experience, prosecutors, with access to evidence, witnesses, law enforcement agencies and laboratories, are in the best position to correct past injustices and prevent future ones. And if you were to ask Robert Dewey, I’m sure he would quietly agree.

Julie Selsberg is a senior assistant attorney general in Colorado and head of the Colorado Justice Review Project.