Aaron Hernandez spends his days alone in a 7-by-10-foot cell at the Bristol County Jail and House of Corrections in Dartmouth.
Trying to keep him in line is Sheriff Thomas Hodgson.
"I've talked to him at length. There's a warmth within this person," Hodgson told CNN.
What went wrong?
"Learned behaviors and the environment people grow up in have an incredible influence on who we become," Hodgson said.
Hodgson said he believes in modifying behavior behind bars. He said inmate number 174954 is reading the Bible and another book he suggested.
"I got him reading 'Tuesdays With Morrie,'" the sheriff said.
It examines how to create a centered, meaningful life.
"He was clearly moved by the book. He called his mother and told her she needed to read it," Hodgson said.
The sheriff said he told Hernandez to find his center by turning to his childhood anchor -- his late father.
"You'll never be able to get back to that place that felt comfortable and safe in. And that's only going to happen if you go back and talk to your father. Go back to your cell and talk with your father," Hodgson said.
What did he think about that advice?
"When I'd see him every so often, 'Hey, you do what I asked you?' 'No, but I'm getting' there.' I think at this point he's got a picture that he didn't have before. His dad's picture," Hodgson said.
A photograph of Hernandez's late father sits in his cell.
Hernandez' father -- a well-known athlete in Bristol, Connecticut, himself -- died from complications after a routine surgery when Hernandez was 16.
Hernandez is charged in a 2012 double-killing and last year's killing of Odin Lloyd. He has pleaded not guilty to the murder charges against him.