Sheriff Tom Dart says Alphonzo Hill, 45, of Calumet City, is charged with criminal sexual assault, custodial sexual misconduct and official misconduct.
Hill worked as an emergency medical technician at Cermak Hospital, which on the jail grounds. Cermak allows EMTs to interact with detainees for minor medical issues, including dispensing of medication in jail divisions.
A Cook County Sheriff's Office press release said that in May, Hill was in a minimum-security jail dispensary room with a 46-year-old man who was there for routine care. During that visit, Hill told the man his doctor ordered him to undergo a more detailed medical examination.
Authorities say during that exam, for which Hill was neither authorized nor licensed, the victim realized Hill was not performing the exam, but was instead sexually assaulting him. The victim stopped Hill and left the room to alert authorities, the release said.
DNA evidence later revealed evidence of an assault, the sheriff's office said.
Hill's next court date is set for Jan. 4.