Cold War historian Thomas Wegener Friis caused a stir in April when he claimed to have uncovered the identity of a Danish man that he said was involved in “serious cases” of subversive activities and espionage against his own country. At the time, Friis declined to release the name of the suspected mole for what he called “legal reasons."

Per Michaelsen, a former journalist for Ekstra Bladet, has now been named by Politiken newspaper as the person who collaborated with the notorious East German intelligence agency, Stasi during the Cold War period.

Michaelsen had previously won Ventre's 'Freedom Prize' and many journalism awards for his articles and a book that named the names of Danes that had collaborated with the Stasi.

Friis said he had "no comment" to Politiken’s speculation that Michaelsen was the spy, but the paper reports that he told several people that Michaelsen was the person he found when he uncovered what he called the "worse espionage case in Danish history".

“What he did was ugly and hurt Denmark,” Friis told BT tabloid when he first released his findings. “It shocked me deeply.”

Politiken reported that in 2009 both Friis and a senior German investigator looking into Stasi activities had marvelled that Michaelsen was able to publish the names and aliases of Danish agents and officers working in the Stasi two years before that information was available in the Stasi’s own massive pile of paperwork.

The 70-year-old Michaelsen vehemently denied he was a spy.

“No,” he wrote to Politiken. “I would have been the wrong person to go to. I was blacklisted as a subversive and anti-Soviet. I was kicked out of East Germany on the personal order of Walter Ulbricht [the East German head of state at the time].”