( CNN ) When one man sat down next to a second man in a St. Louis light rail car and asked him his opinion on the shooting of Michael Brown , it was not the beginning of a discussion . It was the start of an assault , police said . The second man , who was white , did n't want to answer the question . Then the first man , who was black , boxed him in the face . Two more African-American men joined in the beating , according to a police report about Monday 's incident . It was caught on surveillance cameras on the MetroLink train and a passenger recorded it with a cell phone and posted the video online . It has gone viral . Police confirmed to CNN that the online images came from the attack . The victim , 43 , was commuting home when a young man in a red T-shirt and cap walked up to him . The victim asked not to be named in media reports . The man asked to use the victim 's cell phone . He declined , and the young man sat down beside him . `` Then he asked me my opinion on the Michael Brown thing , '' the victim told KMOV , `` and I responded I was too tired to think about it right now . '' The suspect , in his 20s , stood up . `` The next thing I know , he sucker punches me right in the middle of my face , '' the victim said . The video showed the suspect unleashing a barrage of punches at the head of the victim , who covered himself with his hand and forearms . The two other men , also in their 20s , joined in , police said . As the train pulled into a station , a security guard saw part of the beating and alerted police . The man in the red T-shirt could be seen on video kicking at the victim 's face before the train 's doors opened and the assailants ran out . The train 's surveillance cameras captured clear images of their faces , which MetroLink passed on to journalists . Police are looking for the three men . They face possible charges of third-degree assault , police said . It is a misdemeanor under Missouri law . The victim was left with bruises on his face and forehead , police said . The first punch dug the frame of his eyeglasses into the skin of his nose , the victim said . He declined to receive medical treatment . But then there was the emotional pain . On the video , people could be heard laughing while the man was beaten . `` I think it was disgusting that people were sort of laughing and smiling about it , '' the victim said . `` And no one offered to help . No one seemed to call 911 . '' Condemnation of the beating has spread across social media , including from people who protested the shooting of Brown last year by a white police officer in Ferguson , Missouri . The officer was not indicted in Brown 's death . St. Louis alderman Antonio French , a vocal community leader in the aftermath of Ferguson , tweeted his disappointment in the beating . `` Mike Brown question sparks MetroLink beating caught on video , '' he wrote . `` This is disgusting . We have a major problem , STL . '' CNN 's John Newsome contributed to this report .
An African-American man in his twenties beats a white man after asking about KMOV . Two more young black men join in the beating , which is caught on cameras .