That’s my scientific wild ass guess also. This has a Chechen feel to it. If the Ukes did this, they are about to have a whole new level of war. Also, Ukes are not usually suicide attack types. So I think its going to be moslems again.
But if its moslems, THAT is a whole other few questions. Moscow has been diplomatically supporting Hamas against Israel. This would be very some low IQ poor timing for moslems to attack Moscow. Which I guess, again points towards moslems.
But wait ... Kadyrov would easily flip for double his 500M yearly from the Kremlim; his daddy sure as hell did, so why not?
Interedasting...