Prosecution at the UN-backed Khmer Rouge tribunal continued to present evidence on Tuesday seeking to connect three former regime leaders in joint criminal conduct.

The three leaders—Noun Chea, Khieu Samphan and Ieng Sary—are charged with atrocity crimes that include genocide. But they are also being charged under a judicial principal known as joint criminal enterprise, which considers each individual responsible for crimes committed by a group.

International deputy prosecutor William Smith introduced an audio interview of Ieng Sary by researcher Stephen Heder in which the former Khmer Rouge foreign minister explained discussions with Pol Pot over evacuating Phnom Penh a year before the regime took over Cambodia in April 1975. In the interview, Ieng Sary explained discussions with Pol Pot and Chinese leader Zhou Enlai about what would happen after the movement took power.

The prosecution has been working to demonstrate a clear hierarchy and leadership within the regime and on Tuesday posited that leaders made collective decisions.

Cambodian deputy prosecutor Chan Dara Reaksmey told the court Tuesday Ieng Sary had seen armed struggle as the primary means of taking over the country, a policy that began openly in March 1970, with China providing weapons.

Nuon Chea, the regime’s ideologue, has said that armed struggle was a secondary consideration to be used only after politics. However, prosecution says he was a part of the decision to use armed might as early as 1967.