to prove that he was a chinese police officer, jiang is showing me many photos of different police badges, training certificates, even portraits of his graduating class at police academy, images that we cannot show on television because they would reveal his identity. jiang says he was sent from his home province to work in xinjiang three times during which he was ordered to arrest hundreds of suspects, all of them ethnic uyghurs. how were the interrogations being conducted? >> translator: beat them, kick them, beat them bruised and swollen, knock their heads on the radiator, police would step on the suspect's face and tell him to confess. >> reporter: jiang says some suspects were as young as 14 and all of the detainees were beaten. were the suspects all men? >> translator: men and women. >> reporter: did you witness women being beaten?