WARREN, Maine (AP) — A Maine prison inmate is facing charges he caused the death of another inmate at the state prison in Warren two years ago.

On Thursday a Knox County grand jury indicted 32-year-old John Thibeault, formerly of Brewer and Orono, on a manslaughter charge in the death of 64-year-old Sheldon Weinstein in April 2009.

Weinstein, who was confined to a wheelchair, died of blunt force injuries suffered at the hands of other inmates.

Immediately afterward, state police opened a homicide investigation. The indictment did not offer any details about why Thibeault was charged.

Immediately after Weinstein’s death, state police opened a homicide investigation.

The Bangor Daily News says Thibeault is serving a 15-year sentence for a 1997 robbery.