I think he was whacked by Gerard Pappa, but there's two theories... one is that they had some sort of beef or old dispute, personal or otherwise. The other is that he swore revenge after his brother Ralph Spero was killed and the family wanted him dead (but probably wanted things to point away from them and maybe gave Pappa the okay off the record?)

-I shot him a coupla' times.
-What's a couple?
-Hmm, more than a couple... Really I don't know the exact amount, maybe I shot him 10 times, 12 times?
-Maybe fifteen?
-Hmm, it could've been fifteen...

-Anthony "Gaspipe" Casso