Patrons on board a Richmond bound train reported that there was a fight on the trailing car. Officers intercepted the train and detained three males. Officers determined that the incident was a mutual combat between all three men. Two of the men declined to pursue a complaint. One man made a citizen's arrest of one of the other men, who was cited and released. The man making the citizen's arrest was found to have an outstanding $10,000 no-cite arrest warrant for theft, held by El Cerrito PD. That man was arrested on his outstanding warrant and was booked at the Berkeley City Jail.