Audio Transcript:

LISA MULLINS: I'm Lisa Mullins, and this is The World, a co-production of the BBC World Service, PRI and WGBH in Boston. Now that the two reporters held for months in North Korea are back home in the United States, some human rights groups in South Korea are speaking up. They're concerned that Euna Lee and Laura Ling May have jeopardized their efforts to help North Korean refugees. In Seoul, South Korea, Jason Strother spoke with some of the human rights groups.

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JASON STROTHER: They call their group the catacombs, a reference to early Christians who gathered in the underground graveyards of ancient Rome to avoid persecution. The modern version is a weekly meeting of Christian missionaries and secular aid workers who travel back and forth to China's border with North Korea. Many try to prevent the trafficking of female defectors. That was the story that Lee and Ling were working on in March when they were captured by North Korean border guards. The activists hear that the two journalists had notebooks, video footage and phone numbers of North Korean refugees and aid workers they met in along the way. And these were taken by the North Korean security forces. Tim Pieters runs Catacombs and overseas missions in northeast China.

TIM PIETERS: For them to be carrying such potentially incriminating evidence with them, is somewhat representative of cases that we've seen in the past, that journalists come into that area not fully prepared for the depths that they may have to deal with. And that's why myself and our organization tends to be extremely cautious about lending assistance in cases where people are not deeply familiar with the terrain , their not familiar with possible consequences if things go south in their investigations.

JASON STROTHER: Pieters says often journalists who come in for a few days, looking for a good scoop, try to use missionaries as fixers. And some reporters might not fully realize the risk they are putting refugees in.

TIM PIETERS: So for journalists to kind of parachute into that area and think that the North Korean refugees are going to be eager to talk, is really a bit naive, and its also assuming that they're going to risk putting themselves on record in case, the record, whether its video, or whether its notes, or whatever, are ever to be confiscated.

JASON STROTHER: Pieters says its hard to know right now if the information that Pyongyang found in Lee and Ling's possession has been put to any use. What is clear about reporting in China on North Korean refugees, is that journalists, activists and defectors can never be too sure who to trust. Peter Jung is a South Korean missionary who spent time inside a Chinese prison for helping North Koreans along the so-called Underground Railroad that runs through China to Southeast Asia. Jung says at the time, one out of five North Koreans in China was in fact an informer. And Jung, and many others believe, Lee and Ling got snared by one of those.

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JASON STROTHER: Jung thinks that the journalists were deceived by a Chinese of Korean dissent. He appeared to be working with a missionary group in northern China. Jung says, he's heard the man had some sort of connection with the North Korean government, and he either alerted border guards about the Americans, or deliberately took them into North Korean territory. Tim Pieters says aid groups are now walking a fine line. On the one hand they need journalists to publicize the humanitarian crisis occurring in China. On the other, Ling and Lee's detention is forcing them to make changes.

TIM PIETERS: It has raised so many flags in that region, without getting into specifics, it just simply means that security measures have to be redoubled. This has become such a sensitive issue, that it complicates matters immensely for protecting the refugees. Its even more necessary to take things more underground and more precautions have to be taken.

JASON STROTHER: In recent months, activists say North Korea has cracked down on Christians and defectors, one women was shot for distributing Bibles, others have been sentenced to long prison terms. For the World, I'm Jason Strother, in Seoul, South Korea.