Now the Russians have confirmed that both the planes were most likely blown apart by Black Widows - Chechen women who have lost their husbands/kids/families/... during the various Russian "incidents" in Chechnya - using the plastic explosive called hexogen or RDX.
"the Tu-154 plane, which crashed en route from Moscow to the Black Sea resort of Sochi.
... the Tu-134 plane which came down on its way to Volgograd in central Russia."
...and the sun shines on regardless...