Prosecutors have asked Cambodia's war crimes court to send former Khmer Rouge prison chief Comrade Duch to jail for 40 years.
The former cadre, whose real name is Kaing Guek Eav, is accused of overseeing 15,000 deaths at the regime's main torture centre in the 1970s.
In his final remarks to the court he was expected to beg forgiveness for his role in the communist movement behind the Killing Fields atrocities.
The former maths teacher has been detained since 1999, when he was found working as a Christian aid worker in the jungle.
