Kim Jung-wook, a South Korean missionary, speaks during a press conference in Pyongyang, North Korea, in this Feb. 27, 2014, file photo. This week marks 10 years since his arrest. Yonhap

North Korea has been a merciless land for Christian missionaries over the decades. But for South Korean believers, it has been even more so.

Since the early 2010s, several pastors and other religious people from the United States, Canada and Australia were convicted of spying and other “anti-state crimes” in North Korea. But through diplomatic negotiations, all of them were eventually freed.

However, this has not been the case for six South Korean nationals, including Kim Jung-wook, a Baptist missionary who was arrested 10 years ago this week for such charges.

“Our family is still praying and hoping that he is alive and will be able to return home soon,” Kim Jung-sam, his elder brother, told The Korea Times on Tuesday.

For more than five years before the arrest, he was on a humanitarian mission in Dandong, a Chinese border city where he provided food and other necessities for North Korean visitors and escapees.

After sentencing the missionary to hard labor for life several months later, the authorities in North Korea have refused to reveal any information about him, including whether he is alive ― a rule applied only to South Korean captives. For American Kenneth Bae and Canadian Lim Hyeon-soo, the North permitted visits by diplomats through the Swedish Embassy there.

The regime’s apparent neglect of the South Koreans also suggests even more vicious, rights-violating treatment, said Lee Kyu-chang, a senior analyst at the Korea Institute for National Unification, a state-funded think tank.

“There is a possibility that Kim has been suffering from the aftereffects of torture,” Lee said. “South Korean citizens are believed to be under harsher conditions.”

The human rights situation is terrible for everyone in North Korea, not to mention the life of a prisoner. But the regime tends to show some restraint with foreign prisoners as they are potential diplomatic bargaining chips, according to experts.

This is why the government in Seoul should continue to raise the issue, said Shin Hee-seok, a legal analyst at Transitional Justice Working Group, a Seoul-based NGO.

“This issue has largely been overlooked by the government, which I believe could affect how North Korea treats our citizens there as well as the prospect of their release,” he said.

“Over the past two decades, the Japanese government has consistently raised the issue of North Korean abductions of its citizens at the U.N. General Assembly, while the government here has not … What message would its inaction and silence send to North Korea in regard to the detainees?”

As the release of foreign missionaries shows, bringing the South Koreans back is not entirely impossible, he said.

“North Korea has little incentive to keep them, which makes it a relatively more negotiable issue,” he said. “This could bring about a new phase of the inter-Korean relations ― but only if the South Korean government demonstrates its will.”

Christian missionaries and activists offer food and other types of support for North Koreans near its border, putting their own lives at risk. The North Korean constitution protects conditional religious freedom. But in reality, it is non-existent as the regime considers religious activities as an attempt to sabotage its rule.

The Ministry of Unification issued a statement calling for the regime to immediately free all six South Korean captives. The five others include two other missionaries arrested in 2014 ― Kim Kuk-gi and Choe Chun-gil ― and three North Korean escapees who were arrested in 2016 after obtaining South Korean citizenship.