Stig Wennerström (spy)

Stig Erik Constans Wennerström (August 22, 1906 – March 22, 2006) was a colonel in the Swedish Air Force who was convicted of treason in 1964.

During the 1950s, he leaked the Swedish air defence plans and the entire Saab Draken fighter jet project to the Soviet Union. He also worked as a military attaché in Washington, DC, where he was very useful to the Russian military intelligence agency, the GRU. He also served in the same role in Moscow.

As early as 1943, SÄPO, the Swedish Security Service, suspected that Wennerström was working for Germany and in 1947 there were indications that he had connections with the Soviet Union, but the suspicions couldn't be proved. The counter-intelligence operation centred on him was intensified towards the end of the 1950s and his household maid was recruited by SÄPO. In June 1963 the maid reported that she had found some film rolls hidden in the attic. The films contained pictures of secret documents and Wennerström was arrested a few weeks later.

Wennerström was initially sentenced to life in prison, but in 1972 the Swedish government changed the sentence to 20 years, despite the Supreme Commander, General Stig Synnergren, still considering him to be a high security risk. He was paroled in 1974 after serving a total of 10 years; the norm in Sweden at the time was to release prisoners after they had served half their sentences.