Investigators from the Office of Inspector General of the Texas Department of Criminal Justice are investigating after an inmate died following an assault at an East Texas prison.

A preliminary investigation shows that Pete Ayala, 29, from Henderson County, was was assaulted by his cellmate, according to a news release from TDCJ.

Ayala was found unresponsive in his prison cell at the Telford Unit, near New Boston. A prison guard found him while conducting rounds about 4:16 a.m. on Sunday, according to the TDCJ.

The department said Ayala's cellmate was restrained and removed from the cell. The prison staff began lifesaving measures on Ayala and called 911. Ayala was transported to Wadley Regional Hospital in Texarkana, according to TDCJ officials.

He was pronounced deceased by the attending physician at the hospital on June 26, according to prison officials.

Ayala was transfered to the unit in December 2009 to serve a 40-year sentence for murder with a deadly weapon. His cellmate, 22-year-old Justin Williams, was received in November 2016 to serve a 50-year sentence for murder with a deadly weapon.