Kaing Guek Eav alias Duch, the former chief of the Khmer Rouge S-21 security centre, better known as Tuol Sleng prison, died today just after midnight at the Khmer Soviet Friendship Hospital. He was 78.

Neth Pheaktra, the spokesperson for the Extraordinary Chambers in the Courts of Cambodia (ECCC) who announced his death, said Duch is the first person to be convicted by the ECCC of crimes against humanity and Grave breaches of the Geneva Convention 1949.

He was sentenced by the Supreme Court Chamber of the ECCC to life in prison in February 2012, for his role at S-21, the regime’s interrogation centre where as many as 16,000 men, women and children were tortured and brutalised before being systematically killed.

Duch began serving his prison term at the ECCC detention centre in 2012 and was transferred to Kandal Provincial Prison in June 2013 to serve the remainder of his term.

He was admitted to the hospital on Monday at critical condition.

“His death is a reminder to all us that if you commit crimes against humanity, you will be punished until you die.

"He died on the first day of Pchum Ben and this will bring us together, perhaps to remember his many victims as well,” said Youk Chhang, executive director of the Documentation Center of Cambodia (DC-Cam).