The document, and others like it, have reignited a debate on the long-standing but unproven allegations.
Activists in Seoul with the Citizens' Coalition for Human Rights of Abductees and North Korean Refugees released a document they say details a North Korean political prisoner's transfer to a chemical weapons testing facility for the purpose of human experimentation with liquid gas. The document - shown to journalists on Thursday - has what appears to be the official seal of the Number 22 prison camp, which is in the far north of the country.
The document is dated February 13th, 2002 and refers to the transfer of a 43 year-old male named Choi Mun Pyo to one of North Korea's biggest chemical facilities where it is believed insecticides, nerve gas and other agents are produced. The letter is signed by an official named Kim Song Han, but there is no indication of his rank.
Do Hee-yoon, secretary-general of the Citizens' Coalition, says his group hopes this will again focus concern on North Korean abuses.
He says he hopes this document will prove the fact that gas experiments have been conducted on political prisoners in North Korean prison camp Number 22.
Experts in Seoul, including defectors, have not been able to verify the document's authenticity.
South Korean Foreign Minister Jeong Se-hyun reacted cautiously, saying sometimes defectors make sensational claims, but the government is investigating these documents.
The human rights group says the documents, and several others like it, were found by an electrical engineer named Kang Byong-Sop who had access to state security facilities. He is believed to have fled North Korea last year and was detained by Chinese authorities in January while trying to escape to Laos with his family.
Mr. Do and his group are calling for an international response to this information.
Mr. Do says it is North Korea's responsibility to tell the truth. He adds it would be extremely hard to counterfeit an official government seal in North Korea, such as the one this letter bears.
The documents' existence was first reported by the British Broadcasting Corporation. But South Korean security officials and some North Korean defectors in Seoul have expressed doubts about claims made in the controversial program. It included an interview with a defector who says he watched a family being killed with gas as scientists observed.
The B-B-C program, along with the documentation released Thursday, have reawakened activists calls for more international attention on North Korean's political prisons, which are believed to house about 200-thousand inmates.
North Korea, through its official media issued a full denial of the B-B-C report last week, saying it did not gas political prisoners. The North Koreans also criticized Washington, saying it had invented the story to justify waging a war of aggression against them.