Toronto police are searching for three men allegedly involved in a serious assault at a TTC subway station.Investigators say on Sept. 2, three men were on a northbound Line 1 subway train approaching Yorkdale station. At the station, the three allegedly got into an altercation with another person, leaving them with serious injuries before they got back onto the subway and continued northbound.The first suspect is described as having a medium build with short curly/wavy brown hair. He was last seen wearing a black t-shirt, black pants, and black shoes.The second suspect is described as having a medium to heavy build with short brown hair. He was last seen wearing a navy-blue t-shirt, blue denim shorts, black and white Nike Air Force shoes and sunglasses.The third suspect is described as having a medium build with short black hair. He was last seen wearing a button-up shirt, black shorts and tall black rain boots.