PHOENIX -- An inmate attacked a female detention officer during a routine cell search at the Lower Buckeye Jail Monday afternoon, according to the Maricopa County Sheriff's Office.Sheriff Joe Arpaio said Bobby Ruiz jumped on the officer's back, started choking her, wrestled her to the ground then bit off part of her ear."We can't seem to find the part of the ear," Arpaio said. "He may have swallowed it."Other inmates pulled Ruiz off of Officer Rachel Harris and held him down until other officers could get there to help.Harris was transported to a local hospital for treatment."I have ordered this inmate be placed immediately in lockdown and restricted to just bread and water," Arpaio said. Ruiz was in jail on charges of aggravated assault with a deadly weapon. He is expected to face additional charges of aggravated assault against a law enforcement professional.Harris was newly employed with MCSO.