New attention is being focused on a notorious Chechen jihadist warlord, following a string of deadly bombings that has rattled Russia ahead of the Winter Olympics in Sochi. Doku Umarov, the self-proclaimed "emir of the Caucasus," has already claimed responsibility for similar terrorist attacks in the name of Islam — and in a video statement released this summer, he called the Sochi Games tantamount to "demonic dances on the bones of our ancestors" and vowed to "use all means" to stop them. Analysts say that with the major security precautions in Sochi, a major assault at the Olympics is unlikely. But although nobody has yet taken responsibility for the three bombings in Volgograd, a transit hub for the Sochi region, experts are eying Umarov, who broke off from the Chechen insurgency to fight for a single sharia-ruled Islamist state in the region. "The most likely suspect is either Umarov or some group connected to him," one expert said.