The Associated Press

THREE RIVERS, Texas—One inmate was killed and 15 others were taken to hospitals after a riot at a federal prison in South Texas early Friday.

How the inmate died is still being investigated, said Federal Bureau of Prisons spokeswoman Deborah Denham. She did not believe that guards used any potentially lethal force to break up the fight. An autopsy will be performed.

The inmate killed in the riot was identified as Servando Rodriguez, 38. He was serving a 4 1/2 year sentence for violating terms of his supervised release, including marijuana possession with intent to distribute and being in the United States illegally after deportation. Denham didn’t know where Rodriguez was from.

No staff members were injured in the fighting. Three of the hospitalized inmates were released later on Friday. Seven were treated at the prison for minor injuries.

A pair of fights broke out in two housing units at the prison around 7 a.m., when breakfast was wrapping up and guards on the day shift were coming on duty. What sparked the fights and how many inmates were involved is still under investigation, Denham said.

Denham said the incident was brought under control quickly, and the community was never in danger.

The medium-security facility in Three Rivers, located in a rural area 70 miles southeast of San Antonio, has about 1,160 inmates.

The riot was the second at a federal prison in Texas this month. Houston police and firefighters were called to the federal prison in downtown Houston two weeks ago after receiving reports that up to 80 inmates were fighting. A stun grenade was used to stop that brawl.