A fight broke out between two groups of inmates at the John Latorraca Correctional Center on Wednesday, sending one prisoner to the hospital, the Merced County Sheriff's Department reported.
Initially described as a riot, correctional officer and spokeswoman Antoinette Murillo said a review of incident reports indicated it was an "assault" that involved more than 10 inmates.
According to the reports, the inmates in one dorm broke through the shared wall, creating a large hole that allowed them access to prisoners in the adjoining dorm.
At least five inmates sustained minor injuries, including lacerations, and were treated there by medical staff.
One 25-year-old inmate, a Dos Palos resident, was transported to Mercy Medical Center with serious injuries, including lacerations to his head and several other wounds, Murillo said.
The inmate's injuries were not life-threatening. He was returned to the jail Wednesday afternoon, where he is being held on probation violation and carrying a loaded firearm, Murillo said.
The fight broke out around 4 a.m. Wednesday.
Murillo said correctional officers were alerted when they heard loud sounds and screams. The inmates ran back to their cells as officers arrived to break up the fight.
She said officers cleared out the dorm and checked the inmates for injuries, most of which were scrapes and lacerations.
Murillo said it's not clear what was used to create the hole between the dorms. The cause of the fight remains unknown and sheriff's detectives are trying to determine if charges will be filed.
Sheriff Mark Pazin and Undersheriff Tom Cavallero did not return phone calls seeking comment as of press time Wednesday.
Murillo said the facility will be on lockdown, which means there will be no visiting or yard activity for inmates, pending the completion of a review of the incident.
Reporter Ramona Giwargis can be reached at (209) 385-2477 or firstname.lastname@example.org.