A North Korean propaganda video obtained by Voice of the Martyrs portrays Christians as "religious fanatics" and spies" operating on behalf of the South Korean government.
Voice of the Martyrs believes the video was used in training for North Korean security agents to help them identify and root out anyone spreading religion within the hermit communist country.
The video tells the story of a woman called Cha Duksoon who flees to China to find her uncle after suffering from hunger during the Great Famine of the nineties, in which millions are believed to have died.
Arriving in China, she discovers that her uncle is dead but she finds instead the Suhtap Church where she hears the Gospel for the first time and gives her life to Christ.
She is described as "naively" believing a "superstitious" religion and "absurdly trying to establish the 'kingdom of God'".
"Suhtap Church is operated by disguised pastors from the puppet South Korea government's secret service," the narrator says.
"It harbors homeless illegal trespassers, providing anti-republic (anti-North Korean) religious study, effectively training them as spies."
According to the video, Duksoon returns to North Korea, having been sent on a "spying mission" by "the enemy" to establish an underground church network.
"Being superstitious and unfaithful to the republic, Duksoon naively believed the sermons about a merciful God and became a religious fanatic," the narrator says.
"She was completely fooled by the enemy."
The narrator goes on to say that Cha worked as an evangelist and brought together underground Christians for a time of worship and prayer every Sunday.
She was eventually caught by the authorities after being betrayed by a "good and awakened North Korean citizen".
Voice of the Martyrs believes she may have died in a labour camp or been executed by firing squad.
"It is unclear how Deoksun died, but it is possible that she was executed," Voice of the Martyrs said.
The organisation, which supports the worldwide persecuted church, added that Cha had "served the Lord without recognition, just as many North Korean Christians do today, despite their government's attempts to eradicate Christianity".
North Korea is ranked number one on the Open Doors World Watch List of countries where Christians experience the worst persecution.
North Koreans are taught to worship the Supreme Leader, Kim Jong-un. Those who practise Christianity are deemed enemies of the state because they worship God and believe in Him as the ultimate authority above the Supreme Leader.
Christians in North Korea risk imprisonment in camps or prisons, and possibly execution.
The video can be viewed here