LOS ANGELES (AP) — A California inmate serving a life sentence for the murder of seven people is suspected of killing his cellmate at a Kern County jail Friday, the state corrections department said.

Juan Villanueva, 53, was found unconscious around 8:50 a.m. in the cell he shared with Ramón Escobar at North Kern State Prison, California Department of Corrections and Rehabilitation. said in a statement.

Villanueva was pronounced dead a short time later.

The case is being investigated as a homicide and Escobar, 51, is the suspect, the department said. The cause of death will be determined by the medical examiner’s office.

Escobar is serving a life sentence without the possibility of parole after being convicted of five counts of murder. He pleaded guilty to most of the counts and pleaded no contest to the fifth in 2022, according to court records.

Several of the victims were homeless and were beaten to death, authorities said. He also beat and robbed other victims, prosecutors said at the time. Some of the victims were attacked in their sleep and Escobar used a bat or a blunt object.

Escobar, who is originally from Texas, also pleaded guilty to murder in the deaths of his uncle and aunt in that state. Houston’s NBC affiliate KPRC reported At the time.

Villanueva was serving a life sentence with probation for aggravated sexual assault of a child under the age of 14, the Department of Corrections said.

He was sentenced in 2022 and transferred to department custody on February 2.

Escobar has been moved to restricted housing pending the outcome of the investigation, a department spokesman said.