Transcript for Leah Remini: Church of Scientology Wants Me to Fail
To many the church of scientology is known as much for famous follower as it is for its famous or infamous controversies. And they don't take criticism lightly. When former sigh ycientologist leah remini made comments in a public forum it set the stage for a showdown between a powerful organization and one of its highest profile defectors. Dan harris has the story. Going through a personal big change for me and my family. Reporter: In behind the scenes moments from dancing with the stars, leah remini wearing sweat pants and hair back, fires a shot across the bow of the controversial church of scientology. The church is looking for me to fail so they can say to parishioners see what happens when you leave the church. They're waiting for me to fail. Reporter: Remini who starred in the hit sitcom "king of queens." I wanted to perform in the -- Reporter: Not only accused the church of wanting her to fail on dancing with the stars and spoke broadly about her experience in scientology. I was always so scared to be myself. We are used to everything that happens to ourselves is our fault. Used to taking a lot of negativity on yourself. Reporter: Just the latest development in a remarkable story of personal and public faith which broke this past july. Actress leah remini speaks out overnight about her dramatic decision to leave the church of scientology. Reporter: When remini became perhaps the most high profile celebrity defector from the church. I think it is a privilege to call yourself a scientologist. Something you have to earn. Reporter: A church known all over the world for famous members, tom cruise, john travolta. Remini whose mom was a devout believer joined the church of scientology at age 9 and briefly enrolled in the elite order. For years as remini rose through the ranks in hollywood she was a proud public supporter of scientology. According to people close to remini her relationship with the church began to sour in 2006 at the wedding of tom cruise and katie holmes where remini we're told asked the head of the church, tom cruise's best man, where his wife was? She has not been seen publicly in many years making her current whereabuouts a source of feverish speculation among critics. Janet wrightman is the author of inside scientology. She was his wife, close adviser, integral part of every aspect of his life. So her absence has been quite noticed by particularly people who would have been in the upper echelons of the church. Reporter: Remini was we are told friend with shelly. Here they are together at a scientology gala in 2005 in a picture posted by journalist and scientology critic tony ortega. People close to remini say she was berated for asking about his wife. A rebuke that shocked her badly. The church publicly denied the story about remini confronting him at tom cruise's wedding. As for the whereabuouts of shelly miscavage. After the wedding people close to remini say her relationship with the church only got worse. With her private concerns and questions, growing more and more intense, and until this summer when she and her family left scientology. At first, remini was tight-lipped about the departure only saying this to access hollywood. I'm good. I have my family. My real friend are behind me. And I think -- that says a lot. Reporter: Then in august, remini took her face-off with the church to a whole new level. Filing a missing persons report on shelly miscavage. Hours after remini filed the report, the lapd told abc news the case is closed. The report that shelly was missing is unfounded. The church which had handled remini's departure gingerly released a statement saying this ill advised, ludicrous, self promotion and media inquiries it generated caused an inexcusable distraction for the lapd. The episode was nothing more than a publicity stunt for ms. Remini. Janet wrightman argue the church must see remini as a real challenge. Oh, my gosh they're worried about her. Leah remini believed in this. She feels betrayed. Reporter: Many who have left the church of scientology say it can be wrenching they include oscar winning screenwriter paul haggas who called remini brave. And debbie cook, who ran the flagbase in clearwater florida. In court testimony in a now settled lawsuit with the church and also in this interview with "nightline," cook accused church leader david miscavage of being physically abusive. While he never hit her, he did order his secretary to do so. You are in a room with him he tells his secretary to slap you. Yes. Hard enough you fell down? Yes. Why did he ask her to do this? Because he was displeased how I was answering a question -- it wasn't -- it wasn't what he wanted to hear in some way. Reporter: The church says claims that miscavage was abusive are lies. David miscavage's own niece, jenna miscavige hill published "beyond belief" saying leaving the church means she was cut off from friend and family. Sound like leaving is difficult? It is. I have had people who have been my friends, friend my whole life. I can't talk to them. Reporter: The church repeatedly denied members are forced to cut themselves off from former members. My friend leah remini. Reporter: On ellen, leah remini made a similar claim. It's hard. We have lost friends that can no longer talk to us who are in the organization. That is the thing. When you leave the church. They can't talk to you or you can't talk to them or snug. Correct. These are friends that we have had for dozens of years. But I have great friends, other friends that are not in the church. That have stood by us. Our family is stronger and together. That's all I can ask for. You have me. We're your friends. Reporter: On "dancing with the stars" last night it became clear that for remini the wounds are still fresh. Okay. Because you just started working on this. Okay. Okay. You are judging yourself. Leah is hard on herself. This summer she had a difficult experience. To the degree it will affect her, I had no idea. What will this experience do? It will get me out of my head. Out of beating myself up. Out of these bad habits. Reporter: She may think the church is rooting for her to fail. The judges loved remini's samba performance. 8. Reporter: Giving her solid 8s and a standing owe va iing ovation from the crowd and shot to compete next monday night. As for the church they issued a scathing statement saying. We know this may come as a surprise to some one as self absorbed as ms. Remini but we could care less if she wins or loses on "dancing with the stars." For "nightline," dan harris in new york.
This transcript has been automatically generated and may not be 100% accurate.