Chatter filled the venue of Cambodia’s U.N.-backed genocide tribunal Tuesday, as hundreds of people eagerly awaited the arrival of the chief of the Khmer Rouge’s largest and most notorious torture center.

Silence fell as Kaing Guek Eav — alias Duch — was escorted into a courtroom for the first public session of the long-delayed tribunal probing the communist regime’s reign of terror in the 1970s.