The Kejne affair was a political affair in Sweden in the 1950s.

It started in 1948 when Karl-Erik Kejne, a pastor of the town mission, publicly accused homosexual groups to have threatened and made attempts at his life after he had tried to put an end to homosexual prostitution in Stockholm.

This theme was quickly picked up by several evening papers, and reached the proportions of a witch hunt and widespread belief in a conspiracy theory about a "homosexual mafia" controlling several criminal homosexual gangs.

Kejne was accusing the attorney of corruption, specifically by order of cabinet minister Nils Quensel, who, according to Kejne, was involved in the homosexual groups himself. According to Kejne, Quensel also ordered the police to send homosexual infiltrators employed by the police to his house in order to prove that Kejne was himself a homosexual.

A commission was formed to address these issues, and when in 1951, they could not free Quensel from all charges, he chose to resign as a cabinet minister.

The author Vilhelm Moberg wrote lengthily about the Kejne affair and also brought the Haijby affair to public knowledge.

It is still a debated subject whether the conspiracies of the Kejne affair had any resemblance with actual plots, and no one knows for sure what things are true about this whole affair.

See also