SAN DIEGO — Authorities say an inmate has attacked and injured three guards at a state prison in San Diego, knocking one unconscious before being restrained.
Officials are investigating Tuesday evening's attack at the Richard J. Donovan Correctional Facility.
Authorities say 55-year-old Timothy Green hit a correctional officer in the face, knocking him out, then head-butted the face of a lieutenant who tried to subdue him and was finally restrained with the help of another officer.
The guards were treated at a hospital for a head injury, a sprained forearm and a sprained hand. All are expected to recover.
Green wasn't injured and has been placed in segregation pending an investigation.
Authorities say Green is serving 15 years to life for second-degree murder, along with two additional sentences for battery on peace officers.