A video posted to YouTube has sparked an internal investigation in the Louisville Police Department.
It shows officers approaching a man in the infield at Churchill Downs on Derby Day, then pulling him to the ground.
It also shows an officer hitting the man several times before putting a knee on his neck.
The Louisville Police Department is looking into whether the officers violated policies about the use of force.
Police have not identified any of the people involved.
If you want to watch the video in its entirety, click on the link below,