An inmate found unconscious in his cell at the Cumberland County Jail around 9 p.m. Sunday was later pronounced dead at the scene, according to a news release from the Cumberland County Sheriff’s Office.

Miles Hartford, 33, of Leeds was found by a corrections officer who was conducting a security check. Corrections officers and medical staff performed CPR and summoned EMTs, who pronounced him dead, the sheriff’s office said.

The Cumberland County Jail was holding Hartford for the Androscoggin County Jail on charges including operating after suspension, violation of condition of release, operating under the influence and failure to submit to arrest.

Portland police are investigating the death.