I didn’t even look him up, but I’m sure he did, as he’s a Russian diplomat.
My point is that in this case, with the information that’s available, the most likely cause of death is natural.
If additional information comes out, maybe that changes, but a 61 year old man in a high stress job, dying of a heart attack is not suspicious.
Putin assassinating people with this much ambiguity around cause of death, is uncommon.
Ukraine killing people with this much ambiguity would be more believable, but again, we’d need more information to become available for that to make more sense than natural causes.