Former NFL player Lawrence Phillips, whose career was cut short by disciplinary problems, has been found dead inside his California prison cell.

Officials believe Lawrence Phillips, 40, killed himself on January 13.

In the 1990s, Lawrence Phillips was a star player at the University of Nebraska, making him a sought-after rookie in the NFL.

He played for the St Louis Rams, Miami Dolphins and San Francisco 49ers until 1999, but he was plagued by trouble on and off the field.

After his NFL career, Lawrence Phillips continued to have problems with the law.

Eventually, he was sent to prison after being convicted of assault for driving his car into a group of teenagers.

In another case, Lawrence Phillips was convicted of assaulting a former girlfriend.

Lawrence Phillips, who was serving a term of more than 30 years, had been placed in a cell alone after he was accused of killing his former cellmate.

On January 12, a judge found that there was enough evidence to try Lawrence Phillips in the death of Damion Soward, 37.