This People and Power film from 2010 investigated accusations that in 1952 the United States acquired and used germ-warfare technology on North Korea

The film followed professor Masataka Mori as he journeyed inside the secretive regime of North Korea to take eye-witness testimony from survivors of, and witnesses to, the germ-warfare attacks. Together with Professor Mori, who has investigated these claims over a 20-year period, Al Jazeera's team travelled to the villages and townships where the US Army/Air Force allegedly dropped bombs containing infected insects, rodents and food.

Mori's painstakingly acquired trust, and the evidence he has collected, produced a film which is both extraordinary and controversial - not least because it comes at a time when the US and its allies are so determined to prevent North Korea developing nuclear weapons - the most potent of all weapons of mass destruction.

In Harbin, China, Mori located survivors of the wartime Japanese army's Unit 731 responsible for germ-warfare attacks on China. After the war, the man behind this research co-operated with US Army scientists in return for not being prosecuted for war crimes.

Harbin also houses a small research museum dedicated to uncovering the extent of Unit 731's activities - both during the second world war and in the years when the US allegedly adopted it.

The claims put forward by North Korea have been consistently denied by every American administration in the last 60 years. For North Korea, however, the claims only serve to fuel an intense suspicion of the US and its activities in the region.

Professor Hazel Smith of the School of Oriental and African Studies at University of London, and author of 'North Korea: Markets and Military Rule' says the Korea War was a dirty affair on all sides, with countless deaths and an ongoing bloody legacy.

 "The issues about alleged germ-warfare ... a controversial issue in the 1950s and remains a controversial issue now ... there is still no smoking gun evidence that this took place but does form a part of the official discourse about the war," says Smith.

Although Smith doesn't see the allegations as a main talking point for North Koreans on a day-to-day basis, she cannot rule out its impacts on the current political tensions on the Korean Peninsula.

"There are different objectives. The North Koreans want to preserve regime security, which for them means both territorial defence or prevention of military intervention from the outside, but also, security for the current government and those in power.

"They saw what happened to Saddam Hussein in Iraq and what happened to Gaddafi in Libya and their argument is, if these countries had maintained a nuclear programme, they wouldn't have been as vulnerable to invasion from the United States and others.

At the heart of the matter however is that North and South Korea are actually talking to each other now in 2018 in a way that they haven't been in two or three years. There are diplomatic channels that will at least allow for talks on sensitive issues."

Editor's note: This interview has been edited for clarity and brevity. 

Source: Al Jazeera