PHOENIX — Sheriff’s deputies raided two Sizzler steak house restaurants in Phoenix on Saturday, arresting nine employees who are suspected of being illegal immigrants and using fraudulent documents to get jobs.

The raids were part of a yearlong investigation into whether the operators of the two Sizzler locations broke a civil law by knowingly hiring illegal immigrants, Maricopa County Sheriff’s Office Lt. Brian Lee said in a statement.

Deputies were looking for 23 suspects wanted for identity theft, Lee said. Authorities believe one of the suspects was deported three times and has been hired back by Sizzler each time he returned.

The sheriff’s office received a tip from a former Sizzler manager who claimed he had been fired for his refusal to hire employees without the proper documents, Lee said.

“This is another example of a case where desperately needed jobs are being occupied by illegal aliens who have disregarded our laws and our borders,” Sheriff Joe Arpaio said in the statement.

Arpaio, known for pushing the bounds for how local law enforcement agencies can confront illegal immigration, frequently raids workplaces in the greater Phoenix area for people in the U.S. illegally.

A message left at one of the two restaurants wasn’t immediately returned Saturday afternoon. A manager at the other restaurant declined to provide his name and publicly comment on the raid.