Officer Who Forcibly Removed United Airlines Passenger Placed on Administrative Leave

The officer who forcibly removed the United Airlines passenger Sunday night at O'Hare International has just been placed on leave pending an investigation.

The Chicago Department of Aviation said Monday that "the incident on United flight 3411 was not in accordance with our standard operating procedure and the actions of the aviation security officer are obviously not condoned by the Department."

It's unclear which officer the CDA is referring to ... but videos from multiple witnesses on the plane show a man in plain clothes violently grabbing the passenger and dragging him down the aisle ... as 2 uniformed officers follow behind.

Chicago PD said the man started yelling before Aviation Officers tried to forcibly remove him.