A guard was stabbed to death by two inmates at a federal prison in California, officials said.
Jose Rivera was taken to a hospital with stab wounds Friday afternoon and later declared dead, Merced County Sheriff and Coroner Mark Pazin said.
"Our hearts go out to our fellow officers at the federal prison," Pazin said. "Any time you lose an officer, it's always traumatic."
A brief statement released by the U.S. Penitentiary in Atwater said the 22-year-old officer was stabbed by two inmates with homemade weapons.
Pazin said his department will conduct an autopsy while the FBI investigates.
The prison is in the San Joaquin Valley about 64 miles northwest of Fresno.