Lawyers say preparing a parole application based on a claim of innocence is risky, because parole boards want to see inmates say they are sorry. A defendant who lacks remorse is considered more likely to commit other crimes. Indeed, a guilty person who pretends to be remorseful is more likely to be released than a person who says he did not do it, said Daniel S. Medwed, a Northeastern University professor who has studied the issue.

“It is grounded in the 19th-century quasi-religious belief that you have to come to Jesus and admit your sins to be saved,” Professor Medwed said. “Therefore, a prisoner who claims innocence has no real reason for doing it. It’s going to hurt you more than help you.”

The parole board has, in isolated instances, granted parole to inmates who claimed innocence, suggesting a growing acknowledgment of the possibility of wrongful convictions, Professor Medwed said.