Where, what source? Getting in through the back door?
From Wikipedia:
Shortly after his wife’s murder, Duch began attending the prayer meetings of the Golden West Cambodian Christian Church held in Battambang by Christopher LaPel, an evangelical Khmer-American. Duch was baptized by LaPel and eventually became a lay pastor. LaPel was later to observe that although he did not know Duch’s real identity at the time, there were clues. For example, before his conversion, Duch had said to LaPel that he had done a lot of bad things in his life. Later, Duch was to say, “I dont know if my brothers and sisters can forgive the sins I’ve committed against the people”.
Despite Wikipedia being of questionable reliability, I believe this part.