A Chicago Transit Authority bus driver was slightly injured and had his glasses broken when an off-duty Chicago police officer boarded the bus and punched him several times, a transit union official said.
The officer accused the bus driver of cutting him off in traffic and boarded the Route 62 bus State and Monroe, officials said.
The incident happened Saturday night at about 9:20 p.m. and was recorded by the bus' security camera, the Chicago Tribune reported.
According to the Chicago Sun-Times, two officers already on board the bus arrested the off-duty officer following the assault.
Police officials told the Tribune that detectives are investigating and that no charges have been filed against the officer, who had already been relieved of his police powers because of an unrelated matter.