Mr. Russell tried to defend himself with a fireplace poker, but the man wrested it from his hand and beat him until he stopped moving. As the younger man was dressing, Mr. Russell rose to his feet, picked up a small statue and charged. The man took the statue away and delivered several more blows, fatally crushing Mr. Russell’s skull.

A year later, acting on a tip, the police arrested Bruce Reilly. He confessed that he had snapped during the sexual encounter, and that the fight had escalated once Mr. Russell fought back.

“I was reacting — I had stuff built up inside of me,” Mr. Reilly told me. Facing life in prison, he accepted a deal to plead guilty to second-degree murder, and a judge sentenced him to 20 years, followed by 25 years of probation.

Many of Mr. Reilly’s high school friends were shocked, if not entirely surprised. He had always been precocious, but his home life was a mess — his mother was in and out of psychiatric institutions, and he lived in foster care for years as a young child. As a teenager, he dealt drugs and stole license plates. He was accepted to college but didn’t fill out the paperwork in time to qualify for financial aid. He was constantly hustling from one dead-end gig or sketchy apartment to another, until one night he ended up at the home of the man he would kill.

In prison, Mr. Reilly became something of an ascetic. He read and wrote for hours each day and strictly limited his TV intake. He accumulated a small circle of friends who believed he had special insight into surviving incarceration. They would write essays on a chosen topic, like whether democracy was the best form of government, and circulate them for feedback.

When they debated prison reform, their views were a mix of Old Testament justice and New. They came to believe that their dreary sentences were central to their rehabilitation.

“You need to be broken,” Greg Tovmasian, a member of the group, told me. “You need to be completely honest with yourself about why you’re in there. If you’re constantly on the phone, talking to people out there, your head is still in society.” The flip side, they believed, was that if a person had done his grappling and come through it, there ceased to be a point to keeping him locked up.