The Khmer Rouge prison chief known as Duch told tribunal judges on Thursday that every member of the regime’s communist party should apologize and take responsible for the atrocities committed under their rule.

“For the deaths of more than 1 million Cambodians, every party member must be accountable before the people, the nation and the history of humanity,” Duch said. “They must bow [their heads] to say sorry to the people so as to realize what they did was wrong and a tragedy.”

Duch, whose real name is Kaing Kek Iev, is the only former Khmer Rouge leader to ever publicly admit guilt for crimes committed under the regime. None of the other four leaders currently in tribunal custody have ever taken responsibility or apologized to the Cambodian people.

Duch told the court Thursday his repentance was possible because he was a new person, not the math teacher of the 1960s, and not the chief of the Khmer Rouge’s notorious killing machine, Tuol Sleng, he had been.

“I wonder whether the people and the nation of Cambodia have seen me as a new person through this trial,” he said. “Please, let the Cambodian people judge me.”

Duch, 66, is undergoing the first trial of five leaders held by the Khmer Rouge tribunal. He is charged with crimes against humanity, war crimes, torture and murder, for his role as a prison administrator who prosecutors say oversaw the deaths of 12,380 people.

His trial will resume next week with testimony from survivors of Tuol Sleng.