PARK CITY, Utah (Reuters) - Osama bin Laden movie "Zero Dark Thirty" may be an entertaining film, but it fails to capture the true nature of the work of those involved in his hunt and capture, according to three former CIA agents.

Nada Bakos, Cindy Storer and Marty Martin are featured in HBO documentary "Manhunt," which premiered at the Sundance Film Festival this week. It offers an alternative look at the long search by U.S. agents for the al Qaeda leader, who was killed in Pakistan in 2011.

"Zero Dark Thirty," which has been nominated for five Oscars, portrays the hunt for bin Laden through the eyes of a young CIA officer, played by Jessica Chastain, and is described by the filmmakers as based on first-hand accounts.

"It's entertaining. It's a movie, that's the purpose of the film. What it's not, it's not a documentary, it's not a completely accurate portrayal of how national security works, or even how the CIA works," Bakos, a former CIA officer, said of the Hollywood thriller in comments to Reuters.

"Manhunt" attempts to shed light on the larger scale of the operation, dating back nearly 20 years. It focuses on "The Sisterhood" - a team of female CIA analysts leading the search - and "Alec Station," the code name for the larger group involved in the hunt.

All three CIA agents retired from service in 2007 or 2008 and were given clearance to talk to the "Manhunt" filmmakers.

They agreed that the U.S. Navy SEAL team raid scene on bin Laden's Pakistan compound was well done in the Hollywood movie. But they were irked by the "Zero Dark Thirty" portrayal of CIA agent "Jessica," based on real-life agent Jennifer Matthews (played by Jennifer Ehle), who died in a suicide bombing.

"I was so angry at this heated depiction of Jennifer as some fluffy-headed schoolgirl ... I just lost respect for it right there," said Storer, an analyst who tracked bin Laden from 1995.

"The portrayal of who we're supposed to assume is Jennifer Matthews is not accurate. This was not representative of who she was as a person," Bakos added.

TORTURE AND INTERROGATION

Bakos said the controversial "Zero Dark Thirty" torture scenes, included waterboarding and beatings, were "horrific to watch."

And Martin, who ran clandestine operations in top field cases in the 1990s, said, "the interrogation stuff - that was totally inaccurate as well." He declined to be more specific.

In "Manhunt," the CIA search is juxtaposed with journalist Peter Bergen's own insight into al Qaeda.

Bergen produced a CNN interview with bin Laden and correspondent Peter Arnett in 1997 that marked the first time the al Qaeda leader was profiled on U.S. television, when he said he wanted to harm Americans.

Director Greg Barker said he wanted to present as many details as possible by showcasing how both the CIA and how Bergen covered the events, and to structure the documentary in a way that would inform and captivate viewers.

"It was a story that I had to understand for myself, and I saw it also as a spy movie. I make narrative documentary features that play like movies so I wanted to find very compelling characters, who through them, we can enter into the last decade," Barker told Reuters.

Barker said he hoped the documentary would give viewers a better understanding of the detailed search for America's No.1 enemy, and a cause for reflection in future.

"I think there's going to be another crisis, and we'll all want the government to do something to prevent it from happening again. That's what we all felt like after 9/11 ... It's time now to step back and tell this story in a compelling way that people want to watch but also so that people can reflect," Barker said.

"Manhunt" will be shown on cable channel HBO later this year. 

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