On December 9 , 2002 , '' Novaya Gazeta '' published an open letter from Yusuf Krymshamkhalov and Timur Batchaev , Karachai suspects in the 1999 apartment blocks bombings in Moscow and Volgodonsk , to the commission for investigation of this event . In the letter , they claimed that Ugryumov had supervised the bombing campaign on behalf of the FSB , and included an interview with one of main proponents of this theory , historian Yury Felshtinsky . Felshtinsky had passed the letter to the newspaper , and alleged that Ugryumov had committed suicide , possibly under pressure from the FSB
1999 apartment blocks bombings
Russian apartment bombings
German Ugryumov