Cause of death

Turns out it was suicide [1]

That possibility suggested itself during review.

Did it? How so? With the health problems I thought those would have first suspects.

Well, the possibility crossed my mind. Just something about the overall feel of the situation, maybe; in part, perhaps, the impression of his state of mind from the Billboard quote, plus something in one of the sources about the lack of explanation for why he was even in Muscat.