they all got whacked in a shotgun ambush they all hid in closets waited for the signal then lit them up there was blood an guts everywhere even the lookouts ran off

What led the zip faction to throw their weight behind Massino and Napolitano? I've heard references to Indelicato "fucking them over", but how?

I did read that Sonny Red took $1,500,000 worth of heroin on consignment from Sciascia and Lopresti and he never paid for it. Maybe the zips agreed to offer support if there was repercussions or maybe they didn't get their cut?
I also read that The Chin was backing Sonny Red in this deal/scam.......I am not sure how there was no repercussions from someone just outright stealing that amount of product from an ally. The heroin had to have come from the Rizzuto's which maybe led to why Vito cut ties and went independent. Who wants to be allies with someone who steals from you?

At that time the Rizzuto's were still an ally though as Rizzuto and an "old timer" (never heard him identified I don't think) was part of the murder of Sonny Red.

The Rizzuto's proved from day one though they were loyal to nobody but themselves and after New York destroyed itself and they became stronger they figured why bother anymore? Then when Massino clipped George it was all she wrote for sure.