FLORENCE, Ariz. -- The Pinal County Sheriff's Office is investigating the death of a federal prisoner who was being housed at a privately-run prison.
Federal authorities say two prisoners of the U.S. Marshals Service were involved in a fight at the Florence Correctional Center on Saturday morning. One of the inmates died, apparently as a result of injuries sustained during the altercation.
The Marshals Service says the prisoners were from the San Diego area and were being held at Florence pending their transfer to the U.S. Bureau of Prisons.
The sheriff's office says corrections officers were doing an inspection when they saw a 43-year-old prisoner Roberto Venegas-Fernandez assaulting his 55-year-old cellmate, Michael Patrick McNaughton.
The officers were able to enter the cell and subdue the inmate, but the cellmate was pronounced dead.
Deputies say the investigation is ongoing.