The Killing Fields is a 1984 British biographical drama film about the Khmer Rouge regime in Cambodia, which is based on the experiences of two journalists: Cambodian Dith Pran and American Sydney Schanberg. It was directed by Roland Joffe and produced by David Puttnam for his company Goldcrest Films. Sam Waterston stars as Schanberg, Haing S. Ngor as Pran, Julian Sands as Jon Swain, and John Malkovich as Al Rockoff. The adaptation for the screen was written by Bruce Robinson; the musical score was written by Mike Oldfield and orchestrated by David Bedford.

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The important part for answering this question is: The Killing Fields is a 1984 British biographical drama film about the Khmer Rouge regime in Cambodia, which is based on the experiences of two journalists: Cambodian Dith Pran and American Sydney Schanberg. So, the answer is the Khmer Rouge regime in Cambodia , which is based on the experiences of two journalists : Cambodian Dith Pran and American Sydney Schanberg.