The “city frogmen,” a group of divers with the SWAT unit under the administration of the Beijing Municipal Public Security Bureau, are responsible for ensuring the security of the city’s water areas. /VCG Photo

These SWAT divers mainly consist of swimming majors from sports universities, athletes from national wrestling teams and provincial swimming teams or retired elites from the national navy forces. /VCG Photo

SWAT divers usually need to work in the dark, cold and turbid water. Throughout the year, they need to be on duty in the city’s reservoirs, moats and lakes in parks. /VCG Photo

SWAT divers are required to have a large skill base. Patrolling in the waters, their main job is to conduct underwater investigations, catch criminals and eliminate explosive devices. /VCG Photo

“Sometimes when criminals dump the bodies of victims underwater, the quality of the water can be intolerable; but we have to dive in and get the evidences no matter how terrible the conditions are,” said a SWAT diver. /VCG Photo