Nikita Chekulin was head of the Moscow MVD building, part of Lubyanka complex, that Novaya Gazeta jounalist Pavel Voloshin identified as the source of the Hexogen. He defected to London in 2001, took Berezovsky's largesse, friends with Litvinenko, then returned to Moscow and betrayed Berezovsky. Significant part of the process of smearning Berezovsky.