When North Korean authorities caught Jeong Young Sil helping Christians escape to China seven years ago, they did not take her transgression lightly. First, they pulled out her teeth and fingernails to get information about her underground church in the country's northeast. Then, they threw her in prison for four years.
"They demanded to know who was helping me and where they were," says Jeong, an evangelist in her 50s now living in South Korea, who uses an alias to protect her family back home.
Underground churches are particularly feared by North Korean authorities because they're estimated to have helped some 20,000 North Koreans defect to China. As a result, the regime routinely imprisons and executes Christian religious leaders who teach their faith without state approval, according to a U.S. State department report.
South Korean church groups estimate about 100,000 Christians practice in secret churches across the nation now. "We always met for prayer at peoples' homes, in groups of two to keep it private," Jeong says. "When we met in bigger groups, we went far away to the mountains where no one could find us."
Some scholars contend the regime practices a kind of pragmatic tolerance of Christianity, suggesting North Korea's intelligence agency chooses to ignore underground churches because of their political usefulness. "How can they not know the whereabouts of 100,000 Christians?" says Philo Kim, a professor of sociology at Seoul National University in South Korea, who has visited North Korea several times to study Christianity there. "The government takes advantage of them by dispatching spies into the churches. They can gather information about the churches in China and how they help defectors escape."
North Koreans still face execution if they're caught evangelizing. Because useful or not, says Kim, "Among all religions, Christianity is seen as the most threatening to the regime."