LITTLE ROCK, Ark. (AP) — Arkansas prison officials say a convicted murderer was found dead in his cell from an apparent suicide.

The Department of Correction says 52-year-old Anthony Griffin was found hanging in his locked single-person cell at the Ouachita River Correctional Unit in Malvern on Thursday. Correctional officers and medical staff who responded were unable to detect a pulse and Griffin was pronounced dead.

Arkansas State Police will conduct an investigation into the death, and the Department of Correction says it will also conduct an internal investigation.

Griffin was serving life without parole after he was convicted of capital murder in Crittenden County.