a touch judge suffered a broken shoulder when he slipped at anz stadium in sydney as he tried to dodge bottles being thrown by angry canterbury fans at the end of the game on april 3 .
referees had penalised bulldogs captain james graham in the final minute of the game , which allowed south sydney to seal a 18-17 victory .
police have released images of 13 people they are trying to track down as they hunt for the incident .