SACRAMENTO, Calif. (CBS/AP) — Authorities say an inmate has been killed at a Northern California state prison and two other prisoners are suspects in his death.

Officials say the 63-year-old man was stabbed with a homemade weapon in an exercise yard Thursday at California State Prison, Sacramento.

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Guards saw two inmates fighting with him and used pepper spray and a blast grenade to stop the violence.

The dead inmate was serving life without chance of parole at the maximum-security prison east of Sacramento. His name wasn’t immediately released.

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The suspects have been identified as Joshua Kerr and Nicholas Mangelli. Both men have been placed in the prison’s segregation unit.

Mangelli, 28, is serving a life sentence out of Sacramento County without the possibility of parole for first-degree murder and personal use of a dangerous or deadly weapon.

Kerr, 35, is serving a 22-year sentence out of Orange County for second-degree murder with an enhancement for gang activity and second-degree robbery.

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(© Copyright 2019 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)