Chicago ? A Chicago police officer has been charged with aggravated battery after breaking the jaw of a 15-year-old boy who had quarreled with his son, law-enforcement officials said Sunday.

Robert Gallegos, 41, showed little reaction Sunday afternoon as Cook County Judge Israel Desierto ordered him held in lieu of $100,000 bail. Gallegos’ teenage son was involved in a quarrel Wednesday with a fellow student at Juarez High School, and the officer, who was off duty, attacked him in an alley later the same day, according to a statement from Chicago police’s Office of Professional Standards.

In addition to the broken jaw, the teen also sustained bruises, according to officials.

Police spokeswoman Monique Bond said Gallegos, a 10-year veteran, has been relieved of police powers but continues to be paid pending the investigation.