PARK CITY, Utah (TheStreet) -- Alex Gibney, the director of a documentary film about the Church of Scientology, credited Time Warner's (TWX) HBO for staying with the project amid repeated efforts by the church's leadership and lawyers to prevent the movie from going forward.

"I was thrilled in the legal review process how much they stood behind what we're trying to do," Gibney said at the film's premiere Sunday before a packed audience at the Sundance Film Festival. "The lawyers at HBO have been very helpful and very supportive."

The film, Going Clear: Scientology and the Prison of Belief, will be released in theaters in New York, Los Angeles and San Francisco in the coming weeks before being shown on HBO. HBO officials weren't made available for comment at the premiere.

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The film, which is based in part on Lawrence Wright's book of the same name, profiles L. Ron Hubbard, author of the book Dianetics and founder of Scientology, which combines science fiction with psychology and unique views on natural history.

Much of

Going Clear

focuses on the church's current leader David Miscavige and his aggressive efforts to maintain tight control over the activities of its members as he has sought to maintain Scientology's tax-exempt status as a religion.

Gibney had worked with Wright on the 2007 Academy Award-winning documentary Taxi to the Dark Side, which tells the story of an Afghan taxi driver who was tortured to death by U.S. soldiers in 2002 while being held in a military detention center.

Many of the former Scientology members who are featured in Going Clear, including former longtime spokesman Mike Rinder, appeared with Gibney, to answer questions from an audience that gave the film a standing ovation. Rinder has become an activist opposing the church.

"The reason I continue to do this, and why I am so glad the film was made, is that I want the abuses that go on in the church to stop," said Rinder, who left the church in 2007 after 25 years. "I want the mistreatment of people under the guise of religion to end."

Gibney acknowledged that he and others connected to the film did take security precautions at the premiere. Recently, the Church of Scientology took out full-page advertisements in The New York Times and Los Angeles Times criticizing Gibney and attacking the film.

"I've received many cards and letters from the church, but I saw that as very good publicity," Gibney said. "There are security precautions, but I wouldn't say they're overdone. I've done a lot of films about dangerous topics. My view is that speaking out is your best protection."

-- Written by Leon Lazaroff in Park City, Utah

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