It was 10 years ago that filmmaker Kathryn Bigelow first got acquainted with screenwriter Mark Boal. “I had enquired about him when he had written a story for Playboy. I became familiar with him when he turned one of his articles about the war on terror into a television series,” she says. As years passed, they kept in touch and Bigelow approached him when he was covering the Iraq war and she was keen on telling these stories through her film. He went on to write a screenplay titled The Hurt Locker about a fictional set of characters and events based on his interviews and observations in Iraq.

In 2009, Boal, with Bigelow, produced the film that bagged several Oscars, including that for Best Director and Best Film. Now, after four years, the two are back with Zero Dark Thirty that chronicles American efforts to capture and kill Osama Bin Laden.

“I am like a delivery system for Mark’s content. His journalistic credentials have helped me present an unbiased, realistic narrative that is unsentimental and yet aesthetic,” she says. For Boal too, this has been an enriching experience as there is a great mindshare of ideas when they work together. “Kathryn has the ability to take something that is extremely raw and unsentimental and transform it into an intensely moving ‘imagistic version of the reportage’ as she terms it. So, it is great to have that sort of trust and support coming from a director to infuse life and credibility into your writing. I am on the set as the writer, which is somewhat unusual, but terrific for me and useful for Kathryn and the cast,” he says.

Bigelow started working on Zero Dark Thirty — which releases in India on January 25 — six years ago with a very different ending. When US President Barack Obama announced that the US has conducted an operation that killed Osama bin Laden, Mark started talking to sources afresh. “It was all based on a first-hand account, so I felt it was very vivid, vital and immediate,” the director says.

Boal, on his part, did extensive research. He got through to the CIA for access to the Abbottabad raid and the intelligence that led up to it. “We had to stick to real-life evidence and first-hand accounts and change it as per real-time developments,” says Boal, who shot a part of the movie in North India.

Making a movie on a difficult subject like this not only involves great research skills, but also persistence and patience. It was mandatory that Bigelow and Boal worked in tandem, and each one was aware of the other’s work. “The research part was more difficult as there were a lot of controversies on us getting the classified material. And shooting the climax, ‘The raid that killed Bin Laden’, was a task. People know what happened, but they don’t know how it happened,” says Boal.