Is there any possibility of this having to do with the movement against immigrants in Russia?
I doubt it. The Islamist separatists from the Caucasus are usually pretty methodical planners, from what I usually see. With Reuters confirming that it was a “Black Widow” from Dagestan who did this, I would assume that this has been in the works for awhile.
Don’t get me wrong, I’m sure that some people will draw the parallel to score political points. Kind of like a certain Coptic Orthodox film released right before Benghazi (cough cough).