BRIAN BAER, AP
FILE - In this July 26, 1999, file photo, newly-signed San Francisco 49ers running back Lawrence Phillips, center, smiles with 49ers head coach Steve Mariucci, left, and general manager Bill Walsh during a news conference at training camp in Stockton, Calif. California prison officials say former NFL running back Lawrence Phillips has been found dead in his prison cell, and they suspect suicide.

SACRAMENTO, Calif. — California prison officials say former NFL running back Lawrence Phillips has been found dead in his prison cell, and they suspect suicide.

Officials say guards at Kern Valley State Prison found the 40-year-old Phillips unresponsive in his cell shortly after midnight Wednesday. He was pronounced dead about 1:30 a.m.

He had been in segregation since April 2013 after he was suspected of killing his cellmate.

A Kern County judge had ruled Tuesday that there was enough evidence to try Phillips in the death of 37-year-old Damion Soward.

Phillips played for the St. Louis Rams before being released in 1997. He also played for the Miami Dolphins and San Francisco 49ers.

He was convicted of choking his girlfriend and driving his car into three teens in 2005.