Rocco's obit in the Times links to the scene above, but I also like the one below from The Godfather Part II that gives some background on the character.
Moe Greene's name is a composite of real Las Vegas mobsters Moe Dalitz, or possibly Moe Sedway, and Gus Greenbaum. However, Greene's personality is based on Bugsy Siegel.
Greene's death also plays a part in the second film in the series. Greene was a childhood friend to Michael's business partner and rival Hyman Roth, and it is implied that Roth's anger over Greene's murder is one motivation for his plan to destroy Michael.
Hyman Roth, in turn, was:
...a Jewish investor and a business partner of Vito Corleone, and later his son Michael Corleone. He is based on Florida-based mobster Meyer Lansky and was played by Lee Strasberg in the movie.
Jack Ruby, who shot Oswald, was born Jacob Leon Rubenstein in the Maxwell Street area of Chicago, not far from where I currently live. According to his entry in Wikipedia:
G. Robert Blakey, chief counsel for the House Select Committee on Assassinations from 1977 to 1979, sees it differently. He says: "The most plausible explanation for the murder of Oswald by Jack Ruby was that Ruby had stalked him on behalf of organized crime, trying to reach him on at least three occasions in the forty-eight hours before he silenced him forever."
Ruby was seen in the halls of the Dallas Police Headquarters on several occasions after the arrest of Lee Harvey Oswald on November 22, 1963; and newsreel footage from WFAA-TV (Dallas) and NBC shows Ruby impersonating a newspaper reporter during a press conference at Dallas Police Headquarters on the night of the assassination. District Attorney Henry Wade briefed reporters at the press conference telling them that Lee Oswald was a member of the anti-Castro Free Cuba Committee. Ruby was one of several people there who spoke up to correct Wade, saying: "Henry, that's the Fair Play for Cuba Committee," a pro-Castro organization. Some speculate that Ruby may have hoped to kill Oswald that night at the police station press conference. Ruby told the FBI, a month after his arrest for killing Oswald, that he had his loaded snub-nosed Colt Cobra .38 revolver in his right-hand pocket during the press conference.
Another motive was put forth by Frank Sheeran, allegedly a hitman for the Mafia, in a conversation he had with the then-former Teamsters boss Jimmy Hoffa. During the conversation, Hoffa claimed that Ruby was assigned the task of coordinating police officers who were loyal to Ruby to kill Oswald while he was in their custody. As Ruby evidently mismanaged the operation, he was given a choice to either finish the job himself or forfeit his life.
I'll let you read the rest of it and make up your own mind. As for me, every time I decide firmly, one way or the other, that the Kennedy assassination was a conspiracy or not, I change my mind. One thing I have decided, though, is that it looks so much like a conspiracy that maybe, just maybe, it wasn't. Truth, I've noticed, is often stranger than fiction.