Bulgaria was considered Moscow's most loyal ally under Communism, 1944-1989. And its secret service, the Bulgarian DS, was the most subservient to the notorious KGB. The DS spied on its population and in many cases forced its citizens to denounce or inform on friends, even family.
Ekaterina Boncheva from the Bulgarian capital Sofia has spent most of her professional life piecing together the sinister tales left behind by the old Bulgarian secret service. From 2007 till 2025 she was a member of the Bulgarian State Committee on the Secret Files.