BOISE, Idaho (KLIX) Authorities are investigating the death of an inmate at a prison south of Boise after he was assaulted earlier this morning. In a press statement, the Idaho Department of Corrections said Glenn Arthur Cox had been assaulted at just before 1 a.m. today at the Idaho State Correctional Institution. When prison staff got to Cox's cell they found him on the floor and unresponsive. Medical staff attempted CPR and paramedics were called to the prison, but Cox was pronounced dead shortly before 2 a.m. The man assigned to the cell with Cox, James Junior Nice is serving two life sentences out of Twin Falls for murder, was taken to the Idaho Maximum Security Institution while the investigation continues. The Ada County Sheriff's Office is assisting in the investigation.