DELANO, Calif. — On April 30, at 1:30 p.m., correctional officers responded when inmates Matthew Thornton and Michael Arzaga began attacking inmate Robert Hargrave with an inmate-manufactured weapon.

Hargrave suffered multiple stab wounds to his back, chest and abdomen.

Hargrave was then taken to the institution’s Triage and Treatment Area and was later taken to an outside hospital for treatment.

He was pronounced deceased at 2:40 p.m. at the hospital.

Hargrave, 48, had been in prison since May 1994. He was admitted from Riverside County and was serving life without the possibility of parole for first-degree murder.

Inmate Thornton, 38, was admitted from San Diego County on May 11, 2009, to serve a 14-year sentence for attempted second-degree murder and a five-year enhancement for prior felony conviction of a serious offense.

Inmate Arzaga, 47, was received on March 23, 1998, from San Diego County to serve a life sentence with the possibility of parole for second-degree murder.