The film features interviews of former Khmer Rouge officials from the most senior surviving leader to the men and women who slit throats during the regime of Democratic Kampuchea between 1975 and 1979.

He had previously been interviewed by Western and Japanese journalists but he had always denied his responsibility for the killing of people which the Khmer Rouge committed in the Cambodian genocide.

During that time the United Nations-backed Extraordinary Chambers in the Courts of Cambodia (ECCC) was constituted to investigate the alleged crimes of Democratic Kampuchea.

During the same period, Sambath also built up a network of less senior former Khmer Rouge officials and cadres who were prepared to acknowledge and detail their role in the Killing Fields.

[5] Towards the end of the film, Sambath brings Khoun and Suon to meet Nuon Chea and the three former Khmer Rouge comrades try to fathom the lethal history which each of them played a part in.

[6][7] The film also features appearances by Pol Pot, U.S. President Richard Nixon and Deng Yingchao, the widow of Chinese Premier Zhou Enlai.

[8] Pimpaka Towira, managing director of Thai distributor Extra Virgin, said her decision to release the film was difficult at a time when Thailand and Cambodia were engaged in a military conflict.

[23] In March 2011, Sin Chin Chaya told The Wall Street Journal that the permit had not yet been issued because a "formal permission request" had not been submitted.

Due to the film's sensitive nature, the United Cambodian Community organised a pre-screening meeting to prepare elderly survivors of the Killing Fields for what they would see.

[31] In October 2010, Sambath and Lemkin organised an unprecedented dialogue between survivors of the Killing Fields living in California and three former Khmer Rouge perpetrators.

Khoun, Suon and Choeun travelled to Bangkok in Thailand with Sambath for a live 3 hour discussion held via videoconference with the refugees who attended a legal office in Long Beach, California for the event.

"[33] On 15 December 2010, the Los Angeles Times published a feature by Joe Mozingo entitled "Coming to terms with Sadism" which told the story of one man's experience of the October videoconference.

"[38] Andrew Schenker in the Village Voice noted an antecedent in Holocaust cinema: "Taking in Enemies of the People is a little like watching a Cambodian Shoah, but as if we had access to the director's methods and motivations instead of just the astonishing results.

"[39] Diego Costa in Slant Magazine concentrated on the film's journey into the psychological dimension of the violence: "This is an extraordinary historical document, an archive of confessions with potential for closure, atonement, and belated punishment from one single man on a mission.

"[40] Gary Goldstein of the Los Angeles Times found the film "fascinating," writing, "How the genial Sambath remains so circumspect throughout his taut sessions with Chea is remarkable, as is so much of this must-see exposé.

"[41] Elliot V. Kotek in Moving Pictures wrote: "The slow, painful truth is fully revealed in this burning documentary crafted courageously by Sambath and his co-director Lemkin.

"War crimes cinema gets a new wrinkle, or scar of honour, in Rob Lemkin and Thet Sambath's enthralling investigative documentary.

"[45] Derek Adams of Time Out gives the film five out of five stars: "This is patient, persistent, probing and fearless journalism of the highest order and it shocks to the core.

"[46] David Parkinson in Radio Times sounds a note of caution: "The methodology employed by Thet and co-director Rob Lemkin is occasionally manipulative and the truth often remains elusive.

"[47] David Edwards in The Daily Mirror is moved by the film's denouement: "The moment when Sambath reveals the price his own family paid is stirring stuff.

"[48] Ron Wilkinson in Monsters and Critics pays tribute to the journalism, writing: "One of the most amazing investigative documentary films of all time.

"[49] Jared Ferrie focuses on the probative and forensic value of the journalism in The Christian Science Monitor: "In the film, Nuon admits publicly, for the first time, that he ordered the killing of thousands of political opponents, which is probably evidence enough to convict him for war crimes – if he ever makes it to trial.

[58] Sambath and Lemkin continue to blog on their researches, adding material on Nuon Chea's early career and Pol Pot's rise to power in the Khmer Rouge.