After Nhem En arrived in Phnom Penh, he was sent to study political science and military tactics at a technical school. En was again promoted to an elite youth unit and sent to China for training in late 1976, at the age of 15. After the group arrived in Peking, they were divided, some sent to train in military and naval affairs, others in industry or agriculture. Nhem En was selected to study photography. When he arrived back in Phnom Penh, En was assigned to Unit 870 at the Ministry of National Defense under Pol Pot. At the age of 16 he was sent to photograph the incoming prisoners at S-21 Prison.
Even though En had learned only the basics of photography, he was given a studio and several assistants at S-21. Nhem received his daily orders directly from Khmer Rouge interior minister Son Sen and prison commandant Brother Duch: “Every time I met with them they both told me to be very careful when taking photographs, not to ruin or lose them, and to keep them in order. I was also told to keep the darkroom clean and proper…. They told us that we were clean-minded, and we were the representatives of the Angkar.” Nhem said that he was told by Son Sen that the purpose of the photographs was “for conducting investigations on issues about the CIA spies, KGB, Vietnamese.”
