Marty Rathbun, who was once Mr. Miscavige’s top lieutenant, is now one of the church’s top detractors. The churches used to be busy places where members socialized and invited curious visitors to give Scientology a try, he said, but now the church is installing touch-screen displays so it can introduce visitors to Scientology with little need for Scientologists on site.

“That’s the difference between the old Scientology and the new: the brave new Scientology is all these beautiful buildings and real estate and no people,” said Mr. Rathbun, who is among several former top executives quoted by The St. Petersburg Times in a series of articles last year about the church’s reported mistreatment of staff members.

When Mr. Collbran decided he wanted to leave the Sea Org, he was sent to Los Angeles, where potential defectors are assigned to do menial labor while they reconsider their decision. Ms. Collbran remained in Johannesburg, and for three months the church refused to allow them to contact each other, the Collbrans said.

Letters they wrote to each other were intercepted, they said. Finally, Ms. Collbran was permitted to go to Los Angeles, but husband and wife were kept separated for another three months, the Collbrans said, while they went through hours of special auditing sessions called “confessionals.” The auditors tried to talk them out of leaving, and the Collbrans wavered.

They could not just up and go. For one, they said, the church had taken their passports. But even more important, they knew that if they left the Sea Org without going through the church’s official exit process, they would be declared “suppressive persons” — antisocial enemies of Scientology. They would lose the possibility of living for eternity. Their parents, siblings and friends who are Scientologists would have to disconnect completely from them, or risk being declared suppressive themselves.

“You’re in fear,” Mr. Collbran said. “You’re so into it, it’s everything you know: your family, your eternity.”

Mike Rinder, who for more than 20 years was the church’s spokesman, said the disconnect policy originated as Mr. Hubbard’s prescription for how to deal with an abusive spouse or boss.