Syria is for sure to blame

I am not really into conspiracy theory, and particularly the ones that come from the Middle East...but I am almost certain, that this assassination was a professional job, premeditated by the Syrian intelligence...Syria could only carry it out if they could pass off the blame on someone or something else...In this case, Al Qa3da, which would presumebly be an acceptable culprit would dismiss any ties to Syria..Conspiracy? or reality?