Editor's note: This story has been updated with additional information and comment.
An inmate who worked in the kitchen area of the French Robertson Unit 10 miles northeast of Abilene killed correctional officer Mari Johnson, the Texas Department of Criminal Justice alleged in a statement Monday.
Inmate Dillion Gage Compton, 21, attacked Johnson when she entered a storage area, according to the department. Johnson, 55, was found unresponsive early Saturday and later pronounced dead. She began working for the department in 2009.
Compton is serving a 25-year prison sentence related to a 2011 conviction in Dallas County of aggravated sexual assault of a child under the age of 14, according to the agency.
When he was 17, Compton was in the youthful offender program at the Clemens Unit in Brazoria County, according to a 2012 Austin American-Statesman article.
He told the Statesman he was pursuing a job in the computer industry and discussed being placed in solitary confinement for a week after fighting.
"I'm not going back there," he said in 2012. "It was pretty hot."
Following the attack on Johnson, Compton was transferred from the Robertson Unit, a maximum security, all-male facility, to "an undisclosed maximum-security TDCJ unit," according to the agency.
Investigators with the department's inspector general's office are continuing to gather evidence in Johnson's death, and plan to eventually present their findings to the Jones County district attorney's office. The office is investigating the incident as a homicide.
Johnson's death comes almost exactly a year after rookie prison guard Timothy Davison, 47, was beaten to death by an inmate inside the Barry B. Telford Unit in New Boston in northeastern Texas.
Davison was escorting Billy Joel Tracy, 37, on the morning of July 15 when the handcuffed inmate freed one hand from his restraints and began beating the officer. After pulling him to the ground, Tracy began beating Davison with a two-foot "pry bar" tool that guards carry to unlock the small meal tray openings in cell doors.
In 2007, correctional officer Susan Canfield, 59, was killed during an escape attempt at the Wynne Unit in Huntsville.
Johnson's death raises questions, including whether she was alone and working without backup, said Lance Lowry, president of the state's correctional employees union. Staffing, which TDCJ has struggled to maintain, has played a role in attacks on correctional officers, he said.
State leaders' request for budget cuts across state agencies won't help, the union president said.
"The state legislature gutted the agency in 2011, and they're asking for four percent," he said, comparing New York State's 60,000 inmate population and 20,000 correctional officers to Texas' 148,000 inmates and fewer than than 25,000 officers in prisons.
"We can't cut anymore," Lowry said. "This is where the buck stops. We just lost an officer."
Gov. Greg Abbott on Saturday afternoon issued a statement in which he said the state of Texas was mourning for Johnson, saying that she "was senselessly murdered."
Abbott added, "Texas will ensure the perpetrator receives swift justice, and TDCJ has been instructed to take all necessary measures to enhance the safety of their staff to prevent such tragedies."