He Has Been in Solitary Since Bulger's Murder. Why?

It's been six months since mob boss Whitey Bulger was murdered in prison, and authorities have yet to charge anyone. But as NBC News reports, at least one inmate who was sent to solitary confinement after the slaying remains there. Sean McKinnon, 33, does not have any known mafia ties, but he happened to have a cellmate who does: convicted mob hitman Fotios "Freddy" Geas of Massachusetts. As the Boston Globe previously reported, Geas was initially identified as one of two suspects in Bulger's slaying. So do authorities think McKinnon—who is serving time for stealing guns—played a role in the killing or maybe just knows something about it? Not clear.

"He had nothing to do with [Bulger's murder]," his mother, Cheryl Prevost, tells NBC News. "They think he knows more than what he does." She's worried about her son's mental health given that he's alone for 23 hours a day. Geas himself was sent to solitary after the murder, but it's not clear if he remains there. Prison officials will not comment on either situation. A former US attorney says McKinnon might actually be in solitary for his own protection, if other inmates think he played a role or at least knows something. "He's probably in danger no matter what," says Mimi Rocah, now an NBC legal analyst. (Before his death, Bulger told his lawyer he didn't trust the prison officials who transferred him.)