CHICAGO (CBS) — The CTA is investigating a viral video showing a bus driver picking up and body slamming another person.

The short video was posted Thursday morning on Twitter, but it’s unclear from the video when or where the incident happened.

In the video, two men are seen standing in the street next to a CTA bus, facing each other, apparently about to fight, when a man in a CTA uniform rushes in behind one of them, picks him up, and slams him to the pavement.

The CTA employee is then heard shouting “you better get your a** home, boy,” as the man lies motionless on the ground.

A CTA spokesman said the agency is aware of the video and is investigating.

“We find this incident deeply disturbing and are in the process of removing the employees involved from service, pending the completion of our investigation,” a CTA spokesperson wrote in an email. The CTA is not identifying the employee in the video.

At an unrelated press conference Thursday afternoon, Mayor Lori Lightfoot called the video “incredibly disturbing.”

“Both the physical conduct of somebody who looks like they are a CTA employee, the words that were spoken,” she said. “There’s an active investigation ongoing to identify the person who looks like a CTA employee, and really understand the circumstances.”