Not likely. Confirmation that it broke up at altitude.
This Continental commuter broke up mid-air after it lost a tail because of a maintenance screw up. https://en.wikipedia.org/wiki/Continental_Express_Flight_2574 So mechanical failure is possible (although I personally lean toward a bomb based on the info provided). The electrical is a possibility but less likely.
I noticed CNN was floating ‘center fuel tank explosion’ yesterday. “ ...[I]t could have been a center fuel tank that might have exploded.” http://www.cnn.com/2015/11/02/africa/russian-plane-crash-egypt-sinai/index.html (quoting the former managing director of the NTSB)