A pair of Beaver County Sheriff's deputies were injured when they were attacked by three state inmates doing time at the Beaver County Jail.

One deputy was hospitalized after his jaw was broken in three places, Beaver County Sheriff Cameron Noel told the Deseret Morning News. Deputy Troy Anderson underwent surgery on Monday night, but is expected to recover. Deputy Tim Joseph was injured coming to Anderson's rescue.

"He's got some pretty substantial injuries," the sheriff said of Anderson. "I believe he'll be able to recover, but it's going to be a long, drawn out process for him."

Noel said the three state inmates being housed at the Beaver County Jail attacked Anderson on Monday as they were coming in from the recreation yard.

"It was planned out," Noel said. "They jumped him and did what they did to him. They attacked him and got him down on the ground. Within seconds we had another guard come in (Joseph), and they assaulted him."

Deputies swarmed the three inmates and got them into lockdown. They were transported by a Utah Department of Corrections SWAT team to the Utah State Prison in Draper, where they remain in lockdown.

"The investigation is ongoing," said state corrections spokeswoman Angie Welling. "We are working with the Beaver County Sheriff's Office to investigate the incident."

Noel said the inmates have refused to talk.

"They're seasoned prisoners," he said, adding that the three are believed to be members of a Polynesian gang who carried out the attack to elevate their status.

The Utah Department of Corrections identified the inmates as:

Samisoni Kefu, 20, who is serving time for aggravated assault, burglary and assault by a prisoner.

Sione Takai, 22, who is serving time for robbery.

Christopher Olague, 19, who is serving time for forgery, obstruction of justice and false information to a peace officer.

Noel said the attack is under investigation, but he believes it is an isolated incident and did not believe there were any security lapses, or that Anderson or Joseph were singled out.

"In my opinion, it was whoever came to let them out," the sheriff said. "He was the one that was there that let them out."

E-mail: bwinslow@desnews.com