Security Guard Caught On Video Violently Assaulting Unresisting Man On St. Louis Train Platform

A security guard for St. Louis' light rail system punched and stomped on a man lying facedown on a busy platform.
Bystander videos show the guard hitting the man in the head three times with a closed fist and stomping on him as witnesses pleaded for him to stop.
The man was reportedly unresisting and passed out when the guard attacked him.
The security guard has been removed from duty and law enforcement is investigating whether any laws were broken.
The beaten man's condition is unknown.