I'm getting a bit of stimulation (ahem!) to post the answer to this question, so here goes:
A. Mario Lanza.
The famous operatic tenor and movie star had his career cut short by heart problems and continuous battles with obesity. He moved to Italy in the late Fifties. Periodically, he underwent a bizarre weight reduction treatment that put him into an induced coma for weeks at a time. He died during his last treatment, in 1959. The story went around that Charlie Luciano had asked Lanza to sing for him at some affair or occasion, and Lanza refused. So, the story goes, Luciano arranged for Lanza's doctors to make sure he didn't survive the treatment.
Q. Which Mafia guy had Frank Sinatra as the singer at his daughter's wedding?