Greg Scarpa Sr is who I have always thought as the one that tipped off the FBI on the commission meeting, do to Ralph Scotto always complaining about Paul Castellano wanting to meet on every little thing going on in the construction business. The fact that the source had to be someone in the Gambino family to know the exact location of the meeting, excludes Scarpa. I do not believe Joe N. Gallo was the tipster, but a capo in the family.