Two men were caught on a graphic video (below) beating a man June 12 on I-5 in Los Angeles, California.
The video, shot by a witness, has gone viral after airing on YouTube (which removed it) and Live Leak.
In the video, three guys are standing next to their black Volkswagen arguing with a man in a red shirt.
After exchanging words, the man in the red shirt and one of the men from the Volkswagen start fighting, but then a second man from the Volkswagen jumps into the fight.
The two men from the Volkswagen beat the man in the red shirt, before finally knocking him out and kicking him in the face repeatedly.
The men then get back into their Volkswagen and drive off. Another driver gets out of his car and tries to help the man in the red shirt.
California Highway Patrol are now searching for the black Volkswagen, which has a California license plate 3UGW962.
California Highway Patrol spokesperson Mike Harris said: "We don't have any more information other than the video, and we're following up on all the information the video contains. We definitely need to get in touch with the victim."
The man in the red shirt had a concussion and doesn't recall much of the incident.
WARNING: GRAPHIC VIDEO