An inmate at the United States Penitentiary in Tucson died on Sunday after experiencing what officials called "a medical emergency."
Staff found Shelton Harris, 36, in medical crisis and administered life-saving efforts, according to Enoch Jackson, public information officer for the penitentiary. He was transported to a local hospital where he was pronounced dead.
Jackson said the cause of death is currently unknown but that no other inmates were injured nor was there ever any public danger.
Harris entered the prison in February 2016 and was serving a life sentence for murder, conspiracy to commit murder, racketeering, conspiracy to distribute and possession with intent to distribute drugs, possession of a firearm, and witness retaliation.