An ex-Marine pilot who has known Duggan for almost 20 years said it was well known Chinese companies had been recruiting military fliers – and he struggled to comprehend why Duggan would now be targeted for arrest.

“I can’t imagine what secrets he would have, that he would pass along, that would have caused him this much trouble,” said the ex-Marine, who requested anonymity because he still worked for a commercial airline. “I think the China work was pretty well known by most ex-military pilots. I would have first heard about it well over 10 years ago … it’s just that it’s recently made the news.”

Former US military pilot arrested in Australia over work in China

Duggan spent over a decade flying in the US Marine Corps, reaching the rank of Major and working as a military tactical flight instructor, according to his company website.

He moved to Australia after leaving the Marines, with Australian company records listing him as a director in an “adventure flight” company called Top Gun Australia between 2005 and 2014.

The company operated “an initial military training aircraft of the Chinese Air Force” known as a Nanchang fighter jet, according to its website.

“Our Nanchang aircraft are maintained to the same high standard using the maintenance systems used by the Chinese Air Force,” the website said.

Australian company records indicate he moved to Beijing around 2014, listing his address at a flat in Beijing’s upmarket Chaoyang District.

The ex-Marine pilot said Duggan had been “working for a company in China doing CRM training” – referring to cockpit resource management, a set of procedures used to improve flight safety.

He added that Duggan was a skilled pilot who had flown the notoriously-difficult Harrier jump jet in an exchange with the Spanish navy. “Dan was well regarded. That’s a highly sought-after job.”

A Beijing restaurant review in 2017 mentioned an American pilot called Dan Duggan had been running an aviation-themed dive bar called the “Flying Kangaroo” in Chaoyang.

Last week, both the British and Australian governments revealed fears Beijing was poaching retired pilots to train China’s air force in Western military techniques.

“We are taking decisive steps to stop Chinese recruitment schemes attempting to headhunt serving and former UK Armed Forces pilots to train People’s Liberation Army personnel,” the British defence ministry said in a statement.

British media reported that more than 30 pilots had accepted lucrative offers to train China’s military.

Britain steps up efforts to stop pilots helping Chinese military

Chinese foreign ministry spokesman Wang Wenbin denied any knowledge of such employment of British pilots, telling a regular press briefing: “I am not aware of the circumstances you mentioned”.

Australian Defence Minister Richard Marles launched a separate investigation, saying he would be “disturbed” if Australian army pilots were being “lured” to China.