Lawrence Phillips

Former NFL star Lawrence Phillips was pronounced dead after he was found unresponsive in his prison cell Wednesday at Kern Valley State Prison. He was 40.

The former running back’s death was confirmed to USA Today by the California Department of Corrections and Rehabilitation spokeswoman Terry Thornton.

Phillips was sentenced to 31 years in prison in 2009 for plowing his car into a group of teens and assaulting an ex-girlfriend.

At a preliminary hearing on Tuesday, a judge ruled there was sufficient cause to believe Phillips murdered his former cellmate, Damion Soward. A murder trial could have ended in the death penalty for Phillips.

Soward was found strangled to death in April in a prison cell the two men shared. His blood was found on Phillips’ t-shirt and on other items in the cell.

Phillips took the news of his impending death penalty trial hard according to his attorney, Jesse Whitten.

“He started the hearing by telling me, ‘Hey, relax man. I’m going to to be held to answer [for the murder charges]. It’s just a formality.’”

Whitten said Phillips was allowed to wear his street clothes to the preliminary hearing.

“He was like a kid on Christmas morning,” Whitten said. “We got his court clothes. He picked them out. They fit really great, so he was really happy.

“He was very confident about winning this case and he was even optimistic about his appeal on his prior cases,” Whitten told USA Today Sports.

But by the end of the day Phillips had grown frustrated.

“I do think it was hard for him to sit there and listen to people accuse him of this stuff,” Whitten said.

Phillips appeared suicidal in a letter written to his mother dated March 5, 2015.

“I feel myself very close to snapping,” Phillips wrote. “My anger grows daily as I have become fed up with prison. I feel my anger is near bursting and that will result in my death or the death of someone else.”