JAMESTOWN, Calif. (AP) — Officials say they are investigating an inmate’s death at a state prison in Jamestown as a homicide.

Sierra Conservation Center spokeswoman Lt. Leontine von Savoye said on Friday that 31-year-old inmate Andrew Tisnado was found in his bed with severe head injuries two days earlier.

READ MORE: North Highland Family's Home Hit By Thieves After 4 Die In Wrong-Way Crash In Sierra

He was taken by helicopter to an outside hospital, where he died Thursday evening. No one has been arrested in the slaying.

READ MORE: Coyote Likely Behind ‘Suspicious’ Animal Deaths In Citrus Heights, Police Say

Tisnado was one of about 32 medium-security inmates in a dormitory at the prison in Jamestown, about 100 miles southeast of Sacramento. The prison holds nearly 5,000 minimum- and medium-security inmates.

He was sent to prison in January from Los Angeles County to serve a four-year sentence for possessing ammunition as an ex-felon. He was scheduled for parole in November 2015.

MORE NEWS: Family Remembers Woman Killed In Collision Involving Sacramento Metro Fire Ambulance

Copyright 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.