Some call it a manipulative cult. Others say it's a well-established religion that helps people reach their potential.
Since its inception in the 1950s, the Church of Scientology has rarely been far from controversy. And now the Church is under attack again. Former senior insiders claim the Church's current leader, David Miscavige, has created and encouraged a climate of violence within senior staff and was frequently violent himself.
Marty Rathbun was an "Inspector General," a top lieutenant to David Miscavige, and oversaw the Church's legal affairs.
"[Miscavige] viciously beat him, knocked him to the ground," said Rathbun, describing one attack.
Amy Scobee was a Church executive who helped expand Scientology's outreach to celebrities.
"And then [Miscavige] knocked him down in his chair. Um ... to the ground, and he fell down on his back and he was laying on the ground," she said.
Bruce Hines says he was a high level auditor, a kind of therapeutic counselor.
"[Miscavige] just walked up and he hit me on the side of the head..." Hines said.
And supporting their allegations is Mike Rinder, who for many years was Scientology's main spokesman. He is now speaking out against the Church, the same Church he defended to ABC News in 1998.
"I think that there isn't a person on this earth that couldn't benefit from the teachings of Scientology," he said at the time.
The Church's current spokesman is Tommy Davis.
"Nightline" met with Davis at Scientology's New York Church, where he granted us a rare interview.
"Is Mr. Miscavige violent towards Scientologists and has he been physically violent in the past?" we asked.
"Absolutely not," said Davis. "Absolutely not. He is not. He is not and ... it's not in his character, it's not in his nature, and it is not the kind of person he is."
Miscavige spoke at a 2004 Scientology ceremony.
"One quality that has always set us apart is that we are unselfish," he said. "Yes we have an utter monopoly on workable solutions, but we share those solutions with anyone who reaches for them."
In 2004, Miscavige awarded the Church's biggest star and his close friend, Tom Cruise, the "Freedom Medal of Valor," at an elaborate ceremony touting service and good works.
But the private face of Miscavige, according to these former Scientologists, is very different.
"I'll just say it outright. I consider him to be a sociopath," said Hines.
"I think the man's stark-staring mad," said Rathbun.
Energetic and charismatic, David Miscavige quickly moved up the ranks after joining the Church, and became outright leader after Scientology founder L. Ron Hubbard's death in 1986.
Just a few years into his leadership, David Miscavige and Marty Rathbun were battling back against detractors, and after a devastating article in Time magazine, which referred to Scientology as a "thriving cult of greed and power," they decided to go on the offensive.
"I was very much involved in ... litigation that was goin' on on ongoing cases," said Rathbun. "But also, intelligence side of it."
Miscavige agreed to appear live on "Nightline" in 1992. It remains his only television interview.
"If you really looked at the big picture of what's happening in Scientology, it isn't really controversial, certainly to a Scientologist," Miscavige told host Ted Koppel.
The interview included the following exchange: