The death of the former Swedish security service officer-turned-KGB-Cold-War-spy grabbed international attention on Thursday, including the New York Times and the US's ABC News.
His death, first reported on Thursday by Swedish newspaper Dagens Nyheter, was confirmed by Sweden's tax authority, Skatteverket, which records deaths. He died on January 24th. No cause was given.
In recent years, Bergling was diagnosed with Parkinson's disease and lived under the name Eugene Sydholt at an elderly people's home in Stockholm.
The former Swedish intelligence service and military officer's career took him in 1969 to the national security service, now Säpo, but by the 1970s he was selling thousands of classified documents to the Soviet Union during the Cold War era.
He is known to have smuggled out a description of Swedish defence fortifications at the time.
That crime in particular, according to Sven-Åke Hjalmroth, Säpo's director between 1976-1987, caused Sweden great harm.
The former Swedish security service head compared Bergling to Sweden's most notorious spy, Stig Wennerström, an air force officer who spilled secrets to the Soviets for 15 years.
In March 1979, Bergling was arrested by Israeli security police and sentenced by a Swedish court to life in prison for aggravated espionage.
The former Swedish security officer gained in notoriety after escaping prison in 1987 — a major embarrassment for Sweden's liberal prison system which prompted the resignation of the justice minister.
He spent several years in the Soviet Union, Hungary and Lebanon before returning to Sweden in 1994. He served three more years in prison until his release in July 1997.