http://mafia.wikia.com/wiki/William_Bentvena

On or about January 14, 1979, DeSimone was murdered. It was widely speculated that the Gambino family ordered the death of DeSimone, a mob associate with the Lucchese crime family, for his role in the murder of Bentvena. Since Bentvena was a made man, he could not have been killed without permission from the Gambino leadership. Unlike Bentvena, DeSimone was not a made man and was vulnerable. Paul Vario told the Gambinos who murdered the two men. This was done out of revenge for DeSimone attempting to rape Henry Hill's then-wife, Karen, who was having an affair with Vario while her husband was imprisoned. An alternative theory is that the Gambino family did not know about the Bentvena murder and that Gotti may have just wanted revenge for DeSimone's murder of Ronald Jerothe, another Gambino mobster.

At the end for one reason or another, DeSimone would be dead in any case.