As many as 300 inmates, some of them armed with makeshift weapons such as broomsticks, rioted at a privately run prison for illegal immigrants, beating a guard to death and injuring 19 people, a sheriff said Monday.

More than two dozen officers were held hostage at some point during the hours-long spate of violence Sunday, including a group of 15 who had to be rescued by special response teams, Adams County Sheriff Chuck Mayfield said. A gang fight set off the violence, the sheriff said. The guard was killed on the roof of one of the prison buildings.

Sixteen prison employees were treated for various injuries and released from a hospital. Three inmates were hurt, officials said.

The Adams County Correctional Facility holds nearly 2,500 illegal immigrants, with most serving time for coming back to the United States after being deported, said Emilee Beach, a prison spokeswoman. Some of the inmates have also been convicted of other crimes.

The guard killed was identified as Catlin Carithers, who joined Corrections Corporation of America in 2009 and was a senior correctional officer, the Nashville, Tenn.-based company said on its website. CCA is one of the largest private prison companies in the country.

Carithers' cousin, Jason Clark, said the slain guard was engaged and was excited about a recent promotion that took him off the weekend shifts. He had been trained in recent years as part of the prison's special response team and was called into work Sunday to help with the uprising.

"He liked protecting people," Clark said, adding that his cousin had worked as a volunteer firefighter.

It wasn't immediately clear if the gang fight started between members of the same gang or rival groups, but the situation escalated quickly and spread throughout the prison, Mayfield said.

"They had makeshift weapons, broom handles, mop handles, anything they could pull apart, trashcan lids for shields, anything they could grab," Mayfield said. At one point, the inmates set a fire in the prison yard.

Frank Smith, who runs the online prison watchdog group Private Corrections Working Group, said riots are usually caused by poor conditions, but the sheriff said that was not the case.

"The big problem is CCA tries to cut corners in every possible way. They short-staff, the don't fix equipment, and things just get more and more out of control, and that's what leads to these riots. It's just about maximizing short-term profits," he said.

The prison in southwest Mississippi remained on lockdown Monday. Officials were assessing damage.

Federal Bureau of Prisons spokesman Chris Burke said the facility holds low-security inmates.

CCA officials have not responded to questions about what set off the uprising.

"CCA will support full prosecution under the law for all inmates identified as having committed criminal acts during the disturbance," a statement from the company said.

CCA houses about 75,000 offenders and detainees in more than 60 facilities around the country, according to its website.

In 2004, inmates at a different CCA prison in Mississippi set fire to mattresses, clothing and a portable toilet. No injuries were reported. The company announced after that disturbance that it would add about 25 guards at the Tallahatchie County facility.

In Idaho, violence at a CCA-run prison has prompted federal lawsuits, public scrutiny and increased state oversight. In 2010, Vermont inmates being held at a CCA prison in Tennessee were subdued with chemical grenades after refusing to return to their cells.


Associated Press writer Laura Wides-Munoz in Miami, Fla., contributed to this report.