Yassin Musharbash (based in Germany) examines the claim by ISIS(Sinai) that they caused the crash and deaths:
What should we make of the IS claim of responsibility?
He concludes:
So, what should me make of all of this?That's easy:
* This incident should NOT be counted as an IS terror attack (yet).
* We should consider the written claim of responsibility by the IS Sinai province as quite possibly authentic, but not beyond doubt. Furthermore we should bear in mind that even if authentic, it can still be wrong
* We need to look closely at what the technical investigations will tell us
* We should look out for IS publications containing credible pieces of insider information.
Link:http://abususu.blogspot.be/2015/10/w...-claim-of.html

For background on the crash of the Russian owned airliner I have relied upon the BBC's reporting:http://www.bbc.co.uk/news/world-middle-east-34689870