TENNESSEE COLONY, Texas (KETK) – A man serving two life sentences for capital murder in an East Texas prison was murdered by his cellmate, Texas Department of Criminal Justice officials said.

50-year-old Billy Chemirmir was found dead in his cell at the Coffield Unit in Tennessee Colony early Tuesday morning.

Chemirmir was serving two life sentences without parole for two counts of capital murder out of Dallas County. His cellmate, who TDCJ said is serving a sentence for a Dallas County murder, was identified as the suspect in the crime.

Chemirmir was accused of seeking out victims in independent living communities for older people in the Dallas area and was charged with killing 22 elderly women over a two-year span and stealing their valuables.

“This is a conscious, dedicated effort to stalk, surveil, kill, steal, strip and sell,” Dallas County District Attorney John Creuzot said in closing arguments at Chemirmir’s last trial.

Creuzot decided against seeking the death penalty, saying that the two life sentences meant Chemirmir would “die in a penitentiary.”

The Office of Inspector General is investigating Chemirmir’s death.