For most of its existence the Church of Scientology grew and prospered by protecting its secrets. But it’s been tough holding on to that model in the 21st century, a notoriously bad era for powerful institutions in the secret-keeping business. That point has been amply made in recent years by top church officials turned whistleblowers, a high-profile book by Lawrence Wright of The New Yorker, and now a lacerating new HBO documentary based on Wright’s exposé. The new voices in the Scientology debate have both testified to the church’s efforts to silence its critics and, by speaking out, shown the limits of that approach. Their accounts seem to show the church losing its grip on the public narrative it once aggressively controlled.

“The history of Scientology’s attempts to scuttle critical stories goes back decades,” said Stephen Kent, a sociology professor at the University of Alberta who has studied and written about the church.

In 1970, Paulette Cooper, a Harvard graduate in comparative religion with a master’s degree in psychology, began publishing work about Scientology. When’s her book The Scandal of Scientology came out in 1971, it drew the church’s attention.

Internal Scientology documents (revealed in later court documents) described the church’s plan for Cooper, a child of parents killed in Auschwitz during the Holocaust, which was to have her “incarcerated in a mental institution or jail, or at least to hit her so hard she drops her attacks.”

Less extreme examples of Scientology’s reported pressure tactics abound. Former high-ranking Scientologists and experts on the group describe an approach that relies on the threat of legal action and implied negative consequences to dissuade reporters and entertainers from using the church as a subject.

“I know for a fact that some media individuals, media organizations and even academics were scared off from doing stories about Scientology for fear of being sued or otherwise harassed,” Kent said. The professor related a story about being interviewed for a Canadian television production exploring Scientology when, he said, “one of the shows announcers got cold feet” and it never aired.

“Even The Daily Beast knows we do not ‘harass’ the media,” Scientology spokeswoman Karin Pouw wrote in response to a list of questions submitted by The Daily Beast. “This is a myth spread by those who produce one-sided hatchet jobs like Alex Gibney [Academy Award-winning director of the HBO documentary Going Clear] and Lawrence Wright did, but whine when we exercise free speech by pointing out their bias and shoddy methods.”

Mike Rinder knows about Scientology’s approach to dealing with media criticism from experience. Rinder, who’s featured in Going Clear, was a senior executive in the church who spent time in its public affairs division before leaving Scientology.

In 2007 the BBC’s Panorama program began producing a feature, “Scientology and Me.” “The church sent private investigators to follow the BBC’s reporter, John Sweeney,” said Rinder. “The people involved in the production, from Sweeney and his producer all the way up to the top of the BBC, were investigated.”

Pouw, the Scientology spokeswoman, did not address specific claims about the BBC show but wrote in her statement: “The Church does not hire private investigators to follow journalists.”

Rinder, a top official in the church at the time of the BBC program, said he was involved in the operation and saw it firsthand. “I know the church hired [private investigators] to follow Sweeney, as I was there,” he said. “I also saw the reports from them. And John Sweeney video’d them and showed them in his Panorama documentary!”

“That’s basically the tactic the church uses,” Rinder said. Scientology’s approach with its critics, he said, is to “silence them by finding out something that they’re seeking to protect that will either cost them their job or the threat of exposure will cause them to back away.” And “of course, there were also legal threats,” Rinder said.

“Basically that’s the playbook,” Rinder said of the BBC show, “that gets used for every perceived media piece on Scientology.”

At some point, though, that alleged tactic, which left a trail of gaps in the public’s understanding of Scientology where stories were left on the cutting-room floor or never written at all out of fear, apparently began losing its effectiveness.

Ex-Scientologists and experts differ on when exactly they believe the church’s hold on the story of Scientology first started to slip, but they agree on the cause. “The simple answer is the Internet,” said Kent, the University of Alberta sociology professor.

“The ’Net changed everything and from all accounts has had a major impact on membership,” said Mark Bunker, a TV journalist and longtime anti-Scientology activist.

The Internet, of course.

Still, it’s a bit more complicated than that, Kent said. “It’s not just the Internet,” he said. Much of the momentum in the anti-Scientology movement that has culminated in the new HBO documentary comes from ex-members of the church, he said. The Internet gave them a chance to meet each other and trade stories, creating an echo effect that amplified their voices. “Former members became emboldened enough to start speaking on the Internet” about abuses they had allegedly witnessed and, Kent said, that in turn led to more defections and more ex-members speaking out.

“The big change came around 2005, when South Park did their episode on Scientology and ended it with ‘Sue Me,’ and they didn’t get sued,” said Bunker. That lessened the fear among commentators of being sued and, in a dangerous turn for any official piety, opened the group to wider ridicule. Said Kent, “The gravitas of Scientology diminishes rapidly as comedians start picking it apart.”

“The fallout from the first airing of that South Park episode was pretty stunning,” said Bunker. According to Rinder, it led Scientology to scramble to use Tom Cruise’s weight in Hollywood to get the episode quashed.

“When South Park did their program, I went to CAA,” said Rinder, using the abbreviation for Creative Artists Agency, a top Hollywood talent agency that represented Cruise.

Rinder said this is what happened next:

“The Tom Cruise card was played with CAA to get them to put pressure on Comedy Central and Viacom. Ultimately, it really backfired.

After the South Park dustup came other public bruises for Scientology. In 2008, the church found itself in a war with the Internet collective Anonymous. The dispute began over Scientology’s attempts to remove a video from the web that showed Tom Cruise praising the group at an internal church event. That roused an impassioned defense of free speech in a growing online culture that considered the Internet inviolable ground. The back-and-forth ended up generating publicity for Anonymous, which seemed to relish the audience, and exposing Scientology to added and sometimes harsh media attention.

At the same time, Scientology experienced a number of defections by high-level members. Some said they were leaving the church over disputes with its current leader, David Miscavige. And some of those former Scientologists then went public with sharp criticisms of the church and detailed allegations of abuses they claim were carried out by Miscavige or under his authority. In turn those defections supplied some of the critical source material for Wright’s book, which became the basis for Gibney’s new film. And now, coming out on the heels of all the developments that preceded it, the film is generating a wave of press attention that has made it easier to cover Scientology without fear of standing out.

Rinder has another reason he believes the church’s old tactics aren’t as useful as they once were. Litigation as a default response is no longer as effective. That’s because “the first notice of deposition is going to be to [Scientology leader] David Miscavige,” according to Rinder, “and the second note is going to be to Tom Cruise. And that is something that they can’t deal with.”

“They’ve got too many skeletons in their closet and too much they can’t answer to, so their response is to just say everyone’s a liar,” he said.

The church has run an ad campaign attacking the new HBO film that does call nearly everyone involved a liar, criminal, violent psychopath, or some combination of the three.

Scientology’s secrets fill a space both in and outside the organization.

Former Scientologists say that even loyal followers don’t learn about key tenets of church doctrine until they’ve spent years in the church and spent considerable sums for the privilege.

It’s only gotten harder to control the narrative now that HBO’s new documentary, Going Clear: Scientology and the Prison of Belief, has been touring film festivals before its premiere on March 29. The film illustrates the church’s heavy-handed approach to outsiders, but its most harrowing scenes are the ones that purport to show what happens to church insiders who run afoul of Scientology’s leaders.