NEW YORK - Mike Rinder had spent virtually all of his life in the Church of Scientology. From the age of 6 he was raised in the church, eventually rising to become its chief spokesman. Everyone he knew was a Scientologist, including his wife, his two children, his mother, his brother and his sister.

But after spending more than a year in a disciplinary facility known as "the hole," where Rinder said he and other Scientology executives were confined, an increasingly disillusioned Rinder left the church in 2007. It was while in that Los Angeles compound that Rinder, now 59, says he realized the church was "a road to hell" and that he had to get out, even if penniless and without his family.

"I literally walked away with a briefcase," said Rinder, who now lives what he calls "an entirely new life" in Florida with a new wife, a son and a step-son. "A briefcase with nothing in it, but a briefcase."

Rinder's story is one of eight from former church members that make up the emotional arc of the documentary "Going Clear: Scientology and the Prison of Belief," which opens in theaters Friday and will air on HBO on March 29.

Directed by the Oscar-winning documentary filmmaker Alex Gibney and based on the acclaimed book by the Pulitzer Prize-winning journalist Lawrence Wright, "Going Clear" is the highest-profile expose yet of the controversial religion founded by science-fiction writer L. Ron Hubbard.

Substantially on the basis of former members like Rinder speaking out, the film paints a disturbing portrait of Scientology, claiming physical abuse happens regularly; that the church drives wedges between families by labeling non-Scientologist spouses and parents "suppressive persons"; and that the Internal Revenue Service deemed the church a tax-exempt religion in 1993 only because of an avalanche of lawsuits. The documentary also singles out several of Scientology's most famous faces - including Tom Cruise and John Travolta - for not using their power to change the organization.

The church, which declined interview requests for the documentary, has mounted a considerable campaign against the film, including full-page ads in The New York Times and Los Angeles Times and a series of Internet videos. In response to a request for an interview for this story, the church pointed toward videos posted by the Freedom Magazine, which the church publishes.

In those posts and others, the documentary's sources are derided as "bitter, vengeful apostates." The church alleges Gibney didn't present the film's allegations to them for response and calls the film "a one-sided false diatribe." Representatives for the church did meet with Wright, though the church labeled his book "so ludicrous it belongs in a supermarket tabloid."

"Their sources are the usual collection of obsessive, disgruntled former Church members kicked out as long as 30 years ago for malfeasance, who have a documented history of making up lies about the Church for money," said the church in a statement.

The church has also vigorously denied allegations of physical abuse or confinement. It has previously said that managers like Rinder were never held against their will, but were subject to "ecclesiastical discipline."

But Wright and Gibney, with the backing of HBO and The New Yorker (for which Wright writes), bring some heft to their face-off with the church. Wright's New Yorker profile on "Crash" director Paul Haggis, arguably the most famous Scientologist to leave the church, was the magazine's most fact-checked story ever. His book brought rare scrutiny to an organization that has regularly repelled it. "I envisioned that I would have to defend every single word in there," he says. "It's one reason there are very few adjectives."

In a recent interview at HBO's Manhattan offices, just a stone's throw from Scientology's Manhattan office, Gibney, Wright and Rinder spoke of "Going Clear" as empathetic toward those lured to the church, but critical of its enablers.

"We're not attacking the beliefs of the church," says Wright, who previously collaborated with Gibney on the documentary "My Trip to Al-Qaeda." ''You can believe whatever you want to believe and that's fine. It doesn't matter if it's crazy; there are a lot of crazy religions. It's the practices and abuses that are going on in Scientology that I think the book and the film shed light on."

Much of "Going Clear" depends on the testimony of former church members. They do so despite the likelihood of aggressive responses from the church. The church's Freedom Magazine has published harsh appraisals of those it terms "discredited sources." Rinder is labeled "the lady killer." Haggis is called "the Hollywood hypocrite."