BRICKEYS, Ark. — The Arkansas State Police will investigate the death of an inmate who was discovered unconscious in his cell last week.

The state Department of Correction says 50-year-old inmate Anthony Howard died late Friday at the East Arkansas Regional Unit in Brickeys when he didn’t regain consciousness after emergency treatment.

The agency says Howard was serving a 15-year sentence for conspiracy to commit rape, aggravated assault and firearm possession, among other charges.

Howard’s death added to the widespread troubles in Arkansas prisons this year.

Last week, three inmates were injured in a disturbance at a state prison, and state police are investigating more than two dozen cases of unrest, including one in which inmates who had taken keys and a Taser from guards held three correctional officers hostage for three hours.