Youk Chhang
Youk Chhang( born 22 January 1961) is the executive director of the Documentation Center of Cambodia( DC- Cam) and a survivor of the Khmer Rouge's killing fields.
He became DC- Cam ’s leader in 1995, when the center was founded as a field office of Yale University ’s Cambodian Genocide Program to conduct research, training and documentation relating to the Khmer Rouge regime.
Chhang continued to run the center after its inception as an independent Cambodian non-governmental organization in 1997 and is currently building on DC- Cam ’s work to establish the Sleuk Rith Institute, a permanent hub for genocide studies in Asia, based in Phnom Penh.
Ieng Thirith
Ieng Thirith( née Khieu;; 10 March 1932 – 22 August 2015) was an influential figure in the Khmer Rouge, although she was neither a member of the Khmer Rouge Standing Committee nor of the Central Committee.
Ieng Thirith was the wife of Ieng Sary, who was Minister of Foreign Affairs of Democratic Kampuchea's Khmer Rouge regime.
She served as Minister of Social Affairs from October 1975 until the fall of the Khmer Rouge in 1979.
She was the sister of Khieu Ponnary, who was the first wife of Pol Pot.
She was arrested by the Extraordinary Chamber in the Courts of Cambodia( ECCC) in November 2007 with her husband, Ieng Sary, on suspicion of genocide, war crimes and crimes against humanity.
Sak Sutsakhan
General Sak Sutsakhan (8 February 1928 – 29 April 1994) was a Cambodian politician and soldier who had a long career in the country's politics.
He was the last Head of State of the Khmer Republic, the regime overthrown by the Khmer Rouge in 1975.
Sak Sutsakhan formed a pro-US force known as the "Khmer Sâ" (White Khmer).
Hou Yuon
Hou Yuon( 1930 – August 1975?) was a veteran of the communist movement in Cambodia.
A member of the Communist Party of Kampuchea, also known as the Khmer Rouge, he served in several ministerial posts during the 1960s( as a member of the non-communist government of Prince Norodom Sihanouk) and 1970s.
Yuon, who repeatedly clashed with other members of the Khmer Rouge leadership on policy issues, disappeared after 1975.
Reports vary concerning the circumstances of his death.
S-21: The Khmer Rouge Killing Machine
S-21: The Khmer Rouge Killing Machine  is a 2003 documentary film directed by Rithy Panh.
Rithy, himself a survivor of the Khmer Rouge, brought together two former prisoners of the regime with their former captors at Tuol Sleng Genocide Museum, the former Security Prison 21 (S-21) under the Khmer Rouge.
Mong Monichariya
Mong Monichariya is a Cambodian judge and member of the Khmer Rouge Tribunal.
He has been a judge of the Supreme Court since 2002.
Kong Srim
Kong Srim is a Cambodian judge and the president of the Khmer Rouge Tribunal.
His past positions include:
Rithy Panh
Rithy Panh (born April 18, 1964) is a Cambodian documentary film director and screenwriter.
The French-schooled director's films focus on the aftermath of the genocidal Khmer Rouge regime in Cambodia.
Rithy Panh's works are from an authoritative viewpoint, because his family were expelled from Phnom Penh in 1975 by the Khmer Rouge.
One after another, his father, mother, sisters and nephews died of starvation or exhaustion, as they were held in a remote labor camp in rural Cambodia.
Long Boret
Long Boret or Long Boreth( January 3, 1933 – April 17, 1975) was a Cambodian politician who served as Prime Minister of the Khmer Republic from December 26, 1973, to April 17, 1975.
Highly regarded for his honesty, he tried unsuccessfully to negotiate a peace settlement with the Khmer Rouge during the Cambodian Civil War.
He was later arrested by the Khmer Rouge and executed.
He is one of two Prime Ministers to die in office, the other being Chan Sy.
Kang Kek Iew
Kang Kek Iew or Kaing Kek Iev, also romanized as Kaing Guek Eav , "nom de guerre" Comrade Duch or Deuch (មិត្តឌុច); or Hang Pin, (born 17 November 1942) is a prisoner, war criminal and former leader in the Khmer Rouge movement, which ruled Democratic Kampuchea from 1975 to 1979.
As the head of the government's internal security branch (Santebal), he oversaw the Tuol Sleng (S-21) prison camp where thousands were held for interrogation and torture, after which the vast majority of these prisoners were eventually executed.
He was the first Khmer Rouge leader to be tried by the Extraordinary Chambers in the Courts of Cambodia for the crimes of the Khmer Rouge regime, and was convicted of crimes against humanity, murder, and torture for his role during the Khmer Rouge rule of Cambodia and sentenced to 30 years' imprisonment.
On 2 February 2012, his sentence was extended to life imprisonment by the Extraordinary Chambers in the Courts of Cambodia.
Even though he was responsible for the death of thousands of people, Kang Kek Iew, unlike other Khmer Rouge cadres (like Pol Pot), didn't try to dismiss or justify his crimes.
He always admitted that he had been wrong and that he had done horrible things; he said that he repented and that he had converted to Christianity.
Moreover, during the trial, he provided detailed accounts of what happened inside S-21 and inside the Khmer Rouge regime, and this helped shed light on the regime and other cadres' responsibility.

Question: What is the date of birth of the director of film S-21: The Khmer Rouge Killing Machine?
Answer: April 18, 1964