According to the Russian’s, foreigners - Arabs and Turks mostly - travel from cell to cell in the North Caucasus in an advisory role. Could be Chechen’s who can no longer operate at home. It also could just be one specialist who travels from republic to republic, the Caucasus Emirate likes to shift the locus of the insurgency. The Russian’s will likely try to blame the Georgian’s somehow, which could true. As Ken notes, it could also be the internet.

The assassination in Vladikavkaz could have been related to business, politics, organized crime, or a combination thereof. I don’t know much about the incident, other than that it was a good shot.