After three bombings in Volgograd in three months, the name Doku Umarov is coming up frequently as a possible link. Who is the 49-year-old who has dubbed himself the "emir of Caucasus Emirate"? London's Times (via the Australian) calls him "Russia's Osama bin Laden." He pledged in July to "use all means" to stop the Sochi Olympics, which he likened to "demonic dances on the bones of our ancestors." In the 1990s, Umarov was an insurgent against the Russian Federation, NBC News reports. In 2007, after years pushing for Chechen independence, he called for Northern Caucasus to become a united Islamic state under Sharia law.
He and his followers have been linked to a number of attacks. His group claimed responsibility for a 2009 blast at a Siberian hydroelectric plant and an explosion on a Russian train, both of which killed dozens. Umarov said he was behind suicide bombings in 2010 on the Moscow subway and, the next year, at a Moscow airport. Last year, he was said to be involved in an alleged plot to kill Vladimir Putin. The recent attacks bear Umarov's hallmarks, an expert tells the Christian Science Monitor: "The use of women, the use of simultaneous attacks, the use of hitting transportation infrastructure, the repetition of it, these are all the leitmotifs of his work." (Read more Russia stories.)