In June, the board voted to release Frederick Christian, who was 17 when he was arrested for his role in the killing of three men.

“I think this is a very important decision because it demonstrates that the board, as they said in their decision, has an understanding that conduct is affected by the underdeveloped thought process and decision making ability of a juvenile,” said Patty Garin, a Boston defense lawyer who runs a clinic at Northeastern University Law School where students act as counsel for inmates. “I hope that this is a sign of good things to come.”