Some members of the Kovalev Commission appointed to investigate the bombings expressed interest in accounts of possible FSB responsibility for the attacks. Here’s what happened to them: Sergei Yushenkov, co-chairman of the commission and a member of the Liberal Russia party, was assassinated in front of his apartment. Yuri Shchekochikhin, another commission member, independent journalist, and Duma member, was poisoned with thallium. Mikhail Trepashkin was arrested on a weapons charge that later morphed into an espionage case. He was tried in a closed military proceeding and condemned to four years in prison.
A KGB defector, Alexander Litvinenko, wrote a book called Blowing Up Russia alleging that the FSB was responsible for the Moscow bombings. He died, slowly, of poisoning with polonium-210. Litvinenko had also accused Putin of arranging the murder of Anna Politkovskaya — a Russian journalist and critic of Putin and the Chechen war. She was gunned down in the elevator of her apartment building in 2006.