Eleven years later, he died in North Korea in prison, reportedly tortured to death for trying to spread the Gospel in his native land, armed with 20 Bibles and 10 cassette tapes of hymns. He was 50.
His story, pieced together by his younger brother, a defector who lives in South Korea, sheds light on a little-discussed practice: the sending back of North Korean converts to evangelize in their home country.
"It's their country, where people speak the same language. They know where to go and where to escape," says the Rev. Isaac Lee, a Korean-American missionary in Seoul who has dedicated his life to spreading Christianity in the North. "But I agonize a lot whenever I have to send defectors to the North as I know what kind of punishment they would get if arrested."
Officially, North Korea guarantees freedom of religion for its 24 million people. In practice, authorities crack down on Christians, who are seen as a Western-influenced threat to the government.
SON JONG NAM served in the presidential security service for 10 years until his discharge as a master sergeant in 1983. In those years, he was ready to dedicate his life to fighting the "American imperialists," his brother says.
Then in 1997, his wife was arrested for allegedly saying North Korean leader Kim Jong Il had ruined the economy and caused a mass famine. Interrogators kicked her in the stomach, forcing her to have a miscarriage, Son's brother says.
Terrified and disillusioned, Son, then 39, fled in January 1998 with his wife and their 6-year-old daughter to the Chinese border town of Yanji. Son's wife died of leukemia seven months later.
Son grew closer to a South Korean missionary, who had talked to him about Christianity, while sheltering his family after their arrival in China.
Their meeting was not unusual. South Korea has a large Christian population, and hundreds of South Korean, American and Canadian missionaries work undercover in Chinese towns near the North Korean border, say Seoul-based activists specializing in North Korean human rights issues.
They hide Bibles in shipments of food, clothing, and other aid bound for North Korea. They help North Koreans flee and teach them about Christianity.
Son, now a Christian, began helping the missionary try to convert North Koreans hiding in China.
"My brother said he realized the Kim Jong Il regime is hypocritical, and living in accordance with what the Bible says is what we have to do," the younger Son says.
In January 2001, Son was arrested by Chinese police for allegedly trying to convert North Korean defectors in China, which bans foreigners from proselytizing. He was deported home in April, where he was detained and tortured, leaving him with a limp, his brother said.
"He was beaten in the head with clubs and given electric shocks," his brother says, his eyes welling up with tears.
Son was released in 2004 and sneaked across the border to Yanji to see his daughter, who had been left in the care of a Chinese missionary. He soon decided to return to North Korea to proselytize.
"I repeatedly urged him to change his mind, but he told me he has something to do in North Korea," says his brother, who was living in Seoul by then.
Son headed back with the Bibles and tapes. Little is known about how he evangelized, though his brother says Son worked at a state-run defense institute and was allowed to travel freely.
Son was arrested again in January 2006 after police found Bibles at his home in Hoeryong. He was also charged with spying for the United States and South Korea and sentenced to public execution by firing squad.
His brother launched an international campaign to save him. That apparently led his captors to switch to a less public method: torture. "There are many ways to kill people in North Korea," says his brother.
He died in a prison in Pyongyang, the North Korean capital, in December 2008.