Cambodians widely believe the Khmer Rouge was an atheist regime. But in trial testimony this week, jailed prison chief Duch said the regime’s constitution allowed for religion that wasn’t harmful.

The former chief of Tuol Sleng, who is facing atrocity crimes charges at the tribunal, told judges this week that Article 20 of the constitution for Democratic Kampuchea, as the regime was called, allowed for “every citizen of Kampuchea” to have “the right to worship any religion and the right not to worship any religion.”

“Reactionary religions that are detrimental to Democratic Kampuchea and the people of Kampuchea are absolutely forbidden,” it said.

Duch’s testimony about the constitution uncovered another truth about the regime: The words may have been there, but they masked another intent.

“Concretely, the position of this scheme was not to believe in religion whatsoever,” said Youk Chhang, director of the Documentation Center of Cambodia. “The monks were forcibly defrocked, and pagodas became deposits for cells of detention. Cathedrals and mosques were the same, and their believers were accused as enemies and died by oppression.”

In fact, the constitution served “only to hide the crimes the Khmer Rouge expected would happen,” he said.

The constitution also called Democratic Kampuchea an “independent, neutral state,” with “justice managed by Kampuchean people’s court.”