An inmate at California State Prison, Sacramento was killed on the evening of Monday, Oct. 26, after two fellow prisoners attacked him in a housing unit, the California Department of Corrections and Rehabilitation (CDCR) said.

Carlos Montenegro, 39, was pronounced dead at 7:24 p.m. It was the second killing at the Folsom prison this month, KTLA reported.

Correctional staff observed inmates Justin Castro, 47, and Luis Mendoza, 33, attack Montenegro on the upper tier of a housing unit at about 6:43 p.m., according to a CDCR news release. Staff issued verbal orders to stop, but the two men ignored them. Officers then fired five less-lethal 40mm rounds to end the assault.

Staff called 911 and began lifesaving measures on Montenegro while transporting him to the prison's treatment and triage area. Paramedics arrived and pronounced him dead about 40 minutes after the attack began.

Two improvised weapons were recovered at the scene, CDCR said.

Castro and Mendoza were placed in restricted housing pending an investigation by the prison's Investigative Services Unit and the Sacramento County District Attorney's Office. The state Office of the Inspector General was also notified, according to the CDCR release.

No motive has been publicly stated. Whether additional criminal charges will be filed against either inmate remains unclear, KTLA reported.

Montenegro had been at the prison since Sept. 3, 2024, after a transfer from Los Angeles County. He was serving a six-year sentence for assault with a deadly weapon, a second-strike offense, according to CDCR.

Castro was transferred from Los Angeles County on May 8, 2024. He is serving a life sentence with the possibility of parole as a third-strike offender. His convictions include attempted second-degree murder, first-degree burglary, second-degree robbery, kidnapping and carjacking, with a sentencing enhancement for firearm use, CDCR said.

Mendoza arrived from Orange County on March 15, 2017. He is serving a life sentence with the possibility of parole for attempted second-degree murder, second-degree robbery, assault with a semiautomatic firearm and criminal gang activity. His sentence includes enhancements for firearm use and gang-related criminal activity, according to CDCR.

The Oct. 26 killing followed an earlier homicide at the same facility. On Oct. 6, a 47-year-old inmate was killed after another prisoner slipped out of hand restraints during a golf-cart transport and attacked him, KTLA reported. That death is also under investigation.