@ cujet - sorry for the very personal loss to you and anyone else who knew Dr. Masessa.
There's cellphone video out there of the final seconds - rolling turning dive - and as we know, there must be a dozen things that can put a twin-turboprop into such a situation. Sometimes very fast. Especially one of "a certain age." Not often - but rattlesnakes when they do.
https://aviation-safety.net/wikibase/230334