Chen said he was able to behave calmly under such pressure because some words from a former squad leader, who was also his trainer, helped him build a strong mind.

In 2010, Chen was given his first body-retrieval assignment - a dismembered prostitute who had been killed by a client in a dispute over money. Her body was chopped up, with the parts put in sacks and thrown into the Tonghui River, in the capital's Tongzhou district.

"The water was shallow, up to my waist, and I just needed to pick up the parts from the dirty water," he said. "But is was disgusting and scary for a green hand."

Chen said that when he hesitated, the squad leader told him, "You are doing good deeds, to help them out of the darkness."

"His words made me conquer all the fear at that moment," Chen said. "I suddenly felt a kind of awe about my mission: To help the victims leave the water and rest in peace, and to bring the evidence to light. I always keep his words in mind."