"But they added it was unlikely he had been murdered and said he bore no signs of violent injury. Nor was there any indication of a break-in. A police spokesman said: 'At first sight, we are talking about natural causes.'"

I agree, the timing of this is suspicious. However, it appears to be nothing more than a coincidence. Now if this guy had dealings in Turkey, I would say it needs to be further investigated. But then you have to ask yourself the question: what could be gained from his death? The assassination of Andrei Karlov to me seemed like an obvious attempt to provoke a war between Russia and Turkey, during a time in which relations for the two countries were very rocky. The people who were behind his death stood to gain very much from it if Russia had attacked Turkey or vice versa.

But in this case, I'm just not seeing the motive. What could possibly be gained by assassinating this guy? If someone has a plausible theory I remain open minded. Perhaps it could be the same people trying to destabilize relations between Turkey and Greece? That's about the best I can come up with.

could be an inside cleaning job.

Trying to incite a war.