A Chicago police officer has been stripped of his police powers after he was seen in a viral video punching a suspect.

The video was recorded Tuesday in River North. It appears to show the officer striking Lorenzo Williams Jr. three times with a closed fist, while two other officers grab Williams' hair and struggle with him on the ground.

At one point in the video, the officer aims a gun at Williams' face and threatens to shoot him.

The Civilian Office of Police Accountability (COPA) said it has opened an investigation.

The Chicago Sun-Times reported that the officer has been the subject of at least four complaints and seven use-of-force reports. He was also involved in the wrongful raid of the home of social worker Anjanette Young.

Williams, who has a long criminal record, was treated for minor injuries and has been charged with unlawful use of a weapon by a felon.