NEW YORK — The film opens quietly, with a disembodied female voice reading aloud from an e-mail sent by someone who calls himself “Citizenfour.” As we listen to Laura Poitras read, she manages to sound both ethereal and tense, making us feel as though we’re in her head as she wonders whether to trust the mysterious person who would turn out to be Edward Snowden.
“I asked him, ‘How do I know you’re not crazy? Or how do I know this is not entrapment?’ ” Poitras said recently, during an interview at the Soho House hotel. But doubt gave way to overwhelming curiosity after just two or three exchanges, in which Snowden described with impressive specificity a range of electronic government surveillance efforts that Poitras could not find references to anywhere else. That, she said, was when she thought, “OK, this is potentially a huge, big deal.”
Why had Snowden, the computer programmer turned leaker of government documents, chosen Poitras, a filmmaker who grew up in Holliston?
Mostly, it was because he was familiar with her work, including a short film on National Security Agency whistle-blower William Binney, and what she cared about. It also helped that she knew how to use encrypted e-mail — something that Glenn Greenwald, the Guardian reporter whom Snowden had contacted first, had not.
Poitras, whose 2006 film “My Country, My Country” was nominated for an Academy Award, moved to Berlin in 2012, citing government harassment as her reason for leaving the United States. (Poitras has said she was detained and interrogated at US airports roughly 40 times between 2006 and 2012.)
She returned recently for the premiere of her new documentary, “Citizenfour.” And while it’s not her first time back since the Snowden leaks, and her fear of being subpoenaed or indicted is not as powerful as it once was, her inclination has been to stay on her toes.
“It would be naive to think that there aren’t intelligence agents paying attention to who I’m talking to and where I go,” she said, with a bit of exasperation in her voice, like maybe she’s tired of people treating her as if she’s paranoid.
“Citizenfour,” which opens at the Kendall Square Cinema on Friday and is already generating Oscar buzz, tells the story of how Poitras began communicating with Snowden, and how she helped him make public the fact that the US government had been amassing mountains of surveillance data on its citizens. At the movie’s core is about an hour of footage filmed inside a hotel room in Hong Kong during an eight-day trip that Poitras — along with Greenwald and fellow Guardian writer Ewen MacAskill — organized in order to interview Snowden about the surveillance programs and his decision to overturn his life.
“Even though I’ve worked in conflict zones before, this . . . felt more dangerous,” said Poitras, whose last two films were about Iraq and the war on terrorism. “It really did feel more dangerous than working in Baghdad.”
Poitras doesn’t come back to the Boston area often. Growing up, she planned to become a chef, and spent several years as a cook at L’Espalier. Her parents, Patricia and James Poitras, keep a home in Massachusetts, and in 2007 donated $20 million to found a research center at MIT but they mostly live in Orlando, Fla.
After Poitras finished high school (Sudbury Valley School, where there were no grades and no division of students by age), she moved to San Francisco, lost interest in being a chef, and enrolled in art school. She made some experimental films, then found her calling in documentary.
“I left cooking because there were serious limits to what you could do, artistically, to communicate,” Poitras said, speaking in a guarded tone and occasionally looking down at her coffee, as though grasping for the relief of privacy. “When you’re a chef, your job is to please people. . . . You’re there to offer a good experience, not a complicated experience.”
With “Citizenfour,” Poitras has indeed created something complicated: a portrait of Snowden, a visual record of journalism in action, and a story about herself being pulled into history.
And while her byline appeared on the Pulitzer Prize-winning newspaper stories made possible by the leak, making the film was her goal from the start. “We had barely exchanged pleasantries when she got her camera out and got us miked,” Greenwald said in a phone interview.
‘I asked him, ‘‘How do I know you’re not crazy?’’ ’ — Laura Poitras, describing her response to an e-mail Edward Snowden sent to her
Initially, Poitras’s camera had an ironic chilling effect. “Human behavior changes when you know you’re being watched,” Greenwald said. “It makes you stiffer, more self-conscious, less free — which is the danger of surveillance, right? It makes us internally less free.”
Though Poitras was actively involved in what happened in that hotel room, she took a hands-off approach to capturing it on film. Instead of asking Snowden lots of questions about himself and trying to get him to open up, Poitras just watched him with her camera and let him say what he wanted to say. This was in keeping with her “cinéma vérité” approach to filmmaking.
“I really try to be in situations where things are unfolding in real time,” she said, “with the understanding that what people do reveals [more] than what they say about themselves, and how they narrate themselves to the outside world.”
A more traditional journalist might have tried to get past Snowden’s very controlled self-presentation, but Poitras did not, choosing instead to stand aside and let him process, on camera, the magnitude of what he had done and how his life was about to change.
“My general feeling,” Poitras said, “is that a lot of documentaries that are based on interviews — they miss something.”
In a New Yorker Festival interview conducted this month on videophone from Russia, where he was granted political asylum, Snowden said he wants the lesson of his story to be that anyone can do what he did if they believe in something enough. Poitras hopes that “Citizenfour” delivers the same message, and makes audiences believe in their own power to make a dent in the world.
“I think it is an example of how someone can change history — how one person can change history,” Poitras said, adding, “it’s important that we show solidarity with people who take such risks.”