A Youtube video showing Louisiville Metro police officers subduing a man while punching him repeatedly in the back of the neck has prompted an internal investigation.

The incident occurred in the infield of Churchill Downs during the Kentucky Derby earlier this month. It is not clear what crimes the suspect committed because the video only shows police walking up to him as he appears to be kneeling.

At least four officers have him under control while one of them punches him repeatedly as another officer yells “quit fighting, quit fighting.”

However, the man doesn’t appear to be fighting.