Police divers brave dark, dirty world to bring justice to light

Li Xiaona, the squad's deputy head, said conducting security checks of the capital's waterways, especially during big events, remained one of its main duties. The squad checked a water area of 3.5 million square meters last year with the help of boats and underwater sensors.

Another duty is to search waterways for evidence in response to tips or confessions, and bring it to land for forensic or post-mortem investigation, he said.