An attack on a St. Louis commuter-train passenger caught on video is going viral this weekend as investigators search for the suspects responsible for it. The victim, a 43-year-old white male, told police he was asked about Michael Brown before he was beaten Monday night, KTVI-TV reported. Brown, an unarmed black teenager in nearby Ferguson, was shot and killed by Darren Wilson, a white police officer, in the Missouri town last August.

Containing graphic profanity and violence, the viral video was captured by a fellow passenger and uploaded to YouTube. It shows a man seated near the front of a MetroLink train, at first talking with a group of young men. Group members then begin yelling before a man wearing a red hat and shirt strikes the victim in the face.

The victim covers his face with his hands, but neither fights back nor stands up. Several other group members take turns punching him, before the man wearing red kicks him. The train finally comes to a halt, and the perpetrators exit.

Police in St. Louis told KTVI-TV that a security guard witnessed part of the attack, and the perpetrators were caught on surveillance-camera footage, as well. The victim got off the train at the Central West End stop where he talked to police, saying that, before the attack, he was asked about the Michael Brown case. He told police he replied that he had not thought much about it.