April 24, 2008 -- He's one of the biggest box-office draws in history, but in recent years Tom Cruise has become more than just the face of his films. He has also become the face of his religion -- Scientology.

A recent video of Cruise -- made for a Scientology event and leaked online -- showed the star's unbridled passion for his religion and piqued the public's interest in a belief system that has long been surrounded by controversy.

"I think it's a privilege to call yourself a Scientologist," Cruise said in the video.

Cruise is a vocal supporter and close friend of Scientology's worldwide leader, David Miscavige, who took over the reins of power when science fiction author and founder L. Ron Hubbard died in 1986.

Miscavige says Scientology can offer its followers greater ability in all areas of life, rid people of negativity, and make them "clear."

But some former members of the Sea Organization, or Sea Org (Scientology's version of clergy -- the group of people who essentially run the church), including a niece of Miscavige, see another side to the religion. They spoke to "Nightline" about how they became increasingly disillusioned with the Church of Scientology, until they decided it was time to leave.

According to the Church, Scientology is in the midst of tremendous growth. It claims millions of members in more than 100 countries, although critics say those numbers are vastly overstated. But recently, the Church has found itself under increasing attack. In January, a group of online activists known as Anonymous posted a threatening video on the Internet and have since staged a number of anti-Scientology protests across the country. And new Web sites, critical of Scientology, are popping up all over the Internet.

Exscientologykids.com was created by three young women who used to be members of the church, including Jenna Miscavige Hill, who is a niece of Scientology's leader David Miscavige. Hill's parents joined when she was 2 years old. Both her parents were high-ranking members of Sea Org.

"What we're told is that [members of the Sea Org] have to work so hard because they're helping other people," Hill, 24, recalled. "Your family isn't the most important thing."

Life on 'the Ranch' and at Scientology's 'Mecca'

From ages 6 to 12, Hill lived at a Scientology-owned property in California that was known as "the ranch," where she said children as young as 6 had long days. In addition to reading, writing and arithmetic classes and studying Scientology, she said there were physical chores.

"These projects ranged from rock hauling, taking rocks out of the creek, picking them up, hauling them up a hill, putting them in a pile -- these were usually to make rock walls," she said.

As a little girl Hill said she remembers weeding for hours, "no matter how hot or how cold it was outside."

In an official response to a Radar magazine article that included Hill's story, the Church wrote, "Children were never forced to engage in manual labor. Claims to the contrary are categorically denied."

The Church has said about the ranch, which was closed in 1999, that the facilities were "nothing short of spectacular."

Hill said she was asked to sign a billion-year contract to prove her devotion to the Church, because "in Scientology, they believe that you live lifetime after lifetime."

After six years at the ranch, she left California to visit the Church's so-called "mecca" in Clearwater, Fla. She said Church elders asked her to remain there and become a full-fledged member of the Sea Org, while her parents remained in California.

"I wanted to go back and see them," Hill said. "And I was even about to get on a plane, and I just got pulled into a room and screamed at, telling me that, you know, I'm here to be a Sea Org member."

Hill's parents declined our request for an interview.

Sea Org and Suppressive Persons

Hundreds of miles away and unknown at the time to Jenna Miscavige Hill, Astra Woodcraft, 29, was the daughter of Scientologists and as a child also went to Scientology schools and belonged to Sea Org. At age 15, she married a fellow Sea Org member and her days consisted of studying -- mostly Hubbard's teachings -- and clerical duties.

"I worked 15 hour days," she said. "We worked seven days a week. I maybe had only two or three days off a year."

Woodcraft said disobedience wasn't tolerated in Sea Org, and describes the reaction she says she received when she once refused an order from a higher-ranking Sea Org member.

"He held me up against the wall, screaming in my face," she said. "I remember thinking the whole time I was there … on the one hand I was raised on Scientology, I grew up in this environment, I didn't know any different, but I still it was like, this doesn't seem right."

Her father, Lawrence Woodcraft, said the family joined the Sea Org because of his wife's passion for Scientology.

"They paint an extremely rosy picture," he said. "And it sort of sucks you in. [My wife] would happily go for a year or two without seeing [her daughters]. I'm sure she missed them. Her total priority was Scientology, and clearing the planet. When I spoke to her about it, she'd say well, if I don't further the aims of Scientology, the kids won't have a future anyway. It was that level of fanaticism that drove her."

Astra Woodcraft's mother did not return "Nightline's" calls. Lawrence Woodcraft said he grew disillusioned soon after joining the Sea Org and wanted to take his children and leave the Church. But he said he felt that wasn't an option.

"You'll be declared a suppressive person, and then you'll never speak to your family again," he said.

"Suppressive person" or "SP" is Church lingo for someone who is anti-Scientology or, in their terms, "seeks to suppress any betterment activity or group."

"If you leave without permission, they declare you a suppressive person and they make your family and anyone who knows you in Scientology disconnect from you," Astra Woodcraft said.

Despite the risk of being labeled an SP, Lawrence Woodcraft left the church, and he and his wife divorced.

"I was told I couldn't see my dad anymore because he wasn't in Sea Org," Astra Woodcraft said.

Jenna Miscavige Hill also spoke about having contact with her family restricted. She said one day when she was 14 she got in trouble for chit-chatting when she was supposed to be studying. She tried to make a phone call to her parents, but she says she was prevented from doing so and even punched someone during the altercation.

"People were physically stopping me," she said. "Basically I got held down by like three people."

Shortly thereafter, she said, she was confronted by her uncle David Miscavige, who she said told her, "What you did is unacceptable. You're not gonna get any more special treatment," she recalled. "I was like, if special treatment means being held down and not being allowed to talk to your family, then I am happy to be rid of it."

Scientology and Celebrity

Celebrity Center International is a Scientology Church located in Hollywood, Calif. It is aptly named, as many Hollywood celebrities are members of the Church. Cruise and his wife, Katie Holmes, of course, as well as John Travolta and wife Kelly Preston, and Kirstie Alley.

"I had one auditing session in Scientology, and I never did drugs again or had the urge to do drugs again," she told ABC News in a 1998 interview.

Auditing is a fundamental and common practice in Scientology. It's a kind of counseling session in which a person is asked a series of questions and negative feelings and thoughts are identified -- and hopefully purged -- through the use of what's called an e-meter.

"You just basically hold the two cans, and I think they measure electrical resistance," Lawrence Woodcraft said of his auditing sessions. "They have a whole list of questions: Are you withholding anything, do you have an upset over anything. In other words they want to find out what's going on in your life."

Said Jenna Miscavige Hill: "Once a week we would get a meter check where they just have you sit there, and they'd ... observe your needle, and if it's like dirty, then that means that you're hiding something."

Hill said the e-meter and auditing sessions could also be used to interrogate, asking things like: "Do you have any intentions to leave and never come back? Do you talk about bad things about the church to your parents?"

In 2000, Hill's parents were preparing to leave the Church and Hill said that around this time, her e-meter sessions suddenly intensified.

"I just got plucked out of my usual activities by a very high representative of the Church and was interrogated on the e-meter," she said.

Hill also said there were times when she was physically restrained during auditing sessions, "to a point where I was yelling and screaming."

But according to a Scientology report from May 2006, provided to "Nightline" by Hill, the Church said she was the violent one. The report states she had a "long history" of "verbally and physically accosting other staff members … neglecting duties … damaging church property … mayhem … mutiny … enturbulation."

Hill doesn't deny the incidents, but said Church restrictions pushed her to the breaking point.

'No More Kids'?

"I'd been very unhappy while I was there," said Astra Woodcraft, who was becoming disillusioned with the church.

"They came up with a new rule, 'OK, that's it. No more kids,'" she said.

Her father said, "She was very upset when she was about 16 or 17 and told me they suddenly decided to change the rules and Sea Org members were no longer allowed to have children."

Hill said that "if you get pregnant when you're in the Sea Org you either have to leave, or you get an abortion."

Said Astra Woodcraft: "I remember thinking wait a minute, I never agreed to this. I am 17 years old, I haven't made a decision that I'm not going to have children."

Two years after the policy was established, Astra Woodcraft learned she and her husband were expecting a baby.

"A very high-level Sea Org member one day saw me and asked me what I was doing and I said I was leaving and I said I was pregnant and he said, Oh, is it too late for an abortion?," Woodcraft said. "I didn't even know what to say in response. "

In a San Francisco Chronicle article from 2001, Church leaders said that the Church has no policy on abortion, leaving the choice up to individual couples.

Lawrence Woodcraft remembered the relief he felt when his daughter finally decided to leave the church.

"She thought, Wait a minute. There's more to life than Scientology," he said.

"That's when she just took off. Just got the hell out of that rotten organization. … Sorry, it makes me upset to think about it," he said, tearing up.

Soon after Astra Woodcraft left, she divorced her husband and says she was disconnected from her family who was still in the Church.

A few years later, her younger sister left, too.

'I Don't Have a Life'

Jenna Miscavige Hill said it wasn't until years after her parents left the Church that she began to realize she wanted to leave as well. "I don't even have a life," she said of her time in Sea Org. "I don't get to enjoy things. Who am I really helping?"

Hill said she and her husband, Dallas, went back and forth about leaving or staying in the Church. In 2005, they finally left for good, and she said she was told to sign paperwork promising not to talk about her experiences within the Church.

"That's a bond that I didn't sign," she said. "I shredded it in front of the lady's face."

Now out of the Church, Woodcraft, Hill and other ex-Sea Org member started their Web site ExScientologykids.com as a way to connect with other ex-Scientologists.

"It's just a way for people to share stories," said Hill, "And to maybe reconnect with people who they knew before."

With her 9-year-old daughter by her side, Astra Woodcraft said she and Hill are trying to move forward.

"If they would just let people who wanted to be there, be there, and let someone who wanted to leave, leave, and someone who didn't like what was going on, speak their mind, there would be no story," she said.

As for Hill, "I'm not gonna be intimidated. I'm just gonna continue living my life the way I want it to be," she said. "I'm not gonna let them affect me anymore."

Again, Hill's parents -- the brother and sister-in-law of Scientology's leader -- declined "Nightline's" request for an interview. However, Hill said that they have a good relationship now that they are all of out of Scientology.

For weeks, "Nightline" repeatedly asked for an on-the-record response from the Church of Scientology. Thursday night, the Church responded with a statement (CLICK HERE for the full statement) in which the Church says it would not comment on what it called Hill's "dismissal" from her Sea Org position. It goes on to say in part that "Every religion has its detractors; there is no faith that can satisfy everyone's spiritual needs, Scientology included. We wish Mrs. Hill well in her search for spiritual fulfillment."