well as you said,he died on his way on making a movie deal,plus he died in Italy,so you can never tell what really happened.The same thing happened to Costello,he died few days before meeting with an author about a book on his life.

Heres some news paper articles..

http://news.google.com/newspapers?nid=2202&dat=19620210&id=qIElAAAAIBAJ&sjid=2fIFAAAAIBAJ&pg=919,1108962


http://news.google.com/newspapers?nid=1350&dat=19620210&id=uxxPAAAAIBAJ&sjid=ewEEAAAAIBAJ&pg=7336,4781853


...and a dismissal...


http://news.google.com/newspapers?nid=1350&dat=19620607&id=VLxOAAAAIBAJ&sjid=MgEEAAAAIBAJ&pg=5218,5441406