As the first trailer for the Edward Snowden documentary “Citizenfour” reveals, there’s nothing more chilling than a real-life thriller.

The teaser, which was released on Friday before the film’s world premiere at the New York Film Festival, where it received a standing ovation, features interviews with the now-notorious NSA whistleblower.

Director Laura Poitras was already working on a documentary about governmental surveillance in the post-9/11 era when she began receiving emails from “citizenfour,” who wrote, “I am a senior government employee in the intelligence community. I hope you understand that contacting you was extremely high-risk.”

Poitras headed to Hong Kong with reporter Glenn Greenwald to meet with the person she had been corresponding with, who turned out to be Snowden. Snowden ultimately handed over top-secret documents that revealed covert surveillance programs run by the NSA.

The doc, which is exec produced by Steven Soderbergh, opens in theaters on October 24.

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