I'm sure this has been well covered before but;

How come Testa + Senter didn't stay with the Gambino's after Roy's death ?

I know what Casso book says about Reznikov killing.
But, there must be more to it.
Why didn't Gambino's want them ( or kill them otherwise)??
What happened to Gaggis crew? I know they were all in legal trouble but was it disbanded?

Varios crew was very strong in that area and in the car stuff.

** actually I'm very dubious as to Casso's claim to set Roy up. I reckon it was Gaggi and the twins. Although that doesn't answer how the twins joined the luchesses. (sp)

From my understanding, The Gaggi crew was under Greg dePalma after Gaggi.

Originally, it was Paul Castellano's crew so it has been one of a key crews in the Gambino family for a while. Gaggi was Big Paul's protégé and Catsellano made him capo of his crew when he got the top spot.

When Gaggi went to jail / died, John Gotti made Greg dePalma a captain, supposedly as a reward for bringing a major construction company under the control of the Gambinos. At this point, this crew was nothing like the old Gaggi/DeMeo crew. It seems that all the guys from that era have either died or gone to jail so i don't think there was much continuity from the Gaggi crew to the dePalma one.

Gravano has confirmed Casso's claim. He said that Frankie De Cicco was given the contract to kill DeMeo but when he realized he couldn't get close to DeMeo he asked Casso for his help.

I think the Casso story is credible.

Where does Gravano confirm Casso's story? I couldn't find it in his book. He just says DeCicco got members of DeMeo's crew to set him up.

It's strange, but it makes sense though. They did all end up tight with Casso and members of the Lucchese family.

The twins went to the Lucchese family after killing Roy because they bought weed from Casso for years and he knew them. He cut a deal with them, he flat out told them that they had nowhere to go, nobody to trust but him after DeMeo was gone. He said, if they help him kill him he’ll talk to Nino and Paul about them transferring to his family. They saw it as a ticket to membership and they agreed, the rest is history.

That’s not Correct. Gravano said that Decicco was given the contract but couldn’t get to him so he simply handed it off to Roy’s crew specifically the Gemini Twins with Gaggi supervising. Senter and Testa drifted to the Lucchese’s after that

My bad, you're right. I thought he mentioned Casso's involvement in that particular event but he didn't.

No problem no big deal. It happened soon after Roy’s killing so I can I understand thinking Casso has a hand in it but it was just the Gambinos alone