Soon, the Rosato Brothers supposedly killed Frank Pentangeli, faking their service to Corleone in order to convince Frank, one of the Corleone's most long-time supporters, to give up his allegiance.
Believing that Michael ordered him murdered, Pentangeli provides a sworn statement to investigators that Michael is the head of the most powerful Mafia family in the nation, controls virtually all gambling activity in North America, and has ordered countless murders.
After Clemenza's death, Pentangeli took over the Clemenza regime, and headed the Corleone family's operations in New York while Michael and Fredo Corleone were in Las Vegas. He also moved into the old Corleone estate on Long Island.
Michael quickly realizes that Roth ordered the hit. Remembering his father's advice to "keep your friends close, but your enemies closer", he maintains a good business relationship with Roth. Michael also suspects a mole within the Corleone family aided Roth, and needs time to uncover his identity.
First, the Rosado brothers lost a few soldiers during the hit. Second, once Pentangeli had a moment to think everything through, he realized he was turning his back against Corleone (a cardinal sin). One way or another, Pentangeli knew the only way to pay for his betrayal was with his own blood.
Did Frank Pentangeli betray Michael Corleone? & Why Did He Change His Mind?
Why did Pentangeli not testify?
Vincenzo's presence at the hearing was to warn his brother against testifying and thus breaking the code of omertà. The two brothers exchanged a glance before the hearing was called to order. It was enough for Frank to get the message, and he recanted his testimony, blowing apart the government's case.
Fredo was aware that Hyman was angry with Michael's aggressiveness in Las Vegas, and he simply allowed Hyman to attempt to kill Michael so that he could hopefully claim the title of Don Corleone. Of course, we all know how it eventually ended up going down.
Roth arrives at the airport and prepares to be taken into Federal Custody in the U.S. Minutes after getting off the plane, he is shot point-blank by Corleone caporegime Rocco Lampone, who was posing as a reporter. Rocco was then shot and killed by federal officers as he was running away.
Remember, he's based on Meyer Lansky. Lansky was indeed a part of the Jewish Mafia, who worked closely with the Italian Mafias. He made his fortune in the Prohibition era, and he then branched out into other operations. Roth is portrayed a bit differently than the real-life Lansky.
In the novel, Greene is murdered shortly afterward by Al Neri. At the end of the film, Michael has Greene killed as part of his slaughter of the Corleone family's enemies. Neri surprises Greene while he is getting a massage and shoots him through the eye.
Most noteworthy, the novel depicts Clemenza's fatal heart attack (mentioned in The Godfather Part II), and the many conspiracy theories that he had actually been murdered by the Rosato Brothers, former Corleone soldiers who had formed their own gang after a dispute over the future of the family.
Greene is primarily based on Bugsy Siegel, who was also good friends with Meyer Lansky, who inspired the character of Hyman Roth. Like Moe Greene, Bugsy Siegel was also widely mythologized to have been killed with a single, clean, execution-style gunshot through the eye.
Soon after, while Fredo and Neri are fishing on Lake Tahoe, Neri executes Fredo, while Michael watches from his house. Fredo makes a final appearance in the movie's penultimate scene, a flashback to Vito's birthday party in December 1941.
Coppola has said that Vincent is an amalgamation of the five Corleone family males, having his grandfather Vito's cunning, his father Sonny's fiery temper, his uncle Michael's ruthlessness, his uncle Fredo's sensitivity, and his uncle Tom Hagen's unquestioned loyalty.
While in Havana, Michael learned that Fredo betrayed him when Fredo accidentally let it slip that he and Johnny Ola had been to a sex show in Havana. He confronted Fredo at a New Year's party in Havana, telling Fredo that he knew he was the traitor and giving him the "kiss of death".
The third and final film in the Godfather saga, The Godfather: Part III, set in 1979, explains that Hagen had died a few years earlier. His son, Andrew, is ordained to the priesthood, and is assigned to the Vatican on Michael's recommendation. While talking with Andrew, Michael remembers Hagen fondly as a great lawyer.
Enraged, Sonny speeds towards Connie's apartment in Hell's Kitchen ahead of his bodyguards. At the Long Beach Causeway toll plaza, Barzini's men trap Sonny and shoot him to death. During a meeting with the other crime family dons to establish peace, Vito realizes that Barzini masterminded Sonny's murder.
The biggest clue — as events play out in the screenplay of “Godfaher II” — is when Michael realizes that Fredo is the betrayer in the Corleone organization, as revealed by Fredo's lies. Moreover, it's that Fredo's lies reveal that FREDO WAS WORKING WITH ROTH'S HENCHMAN, Johnny Ola. That is the key.
While in Havana negotiating with Roth, Michael realizes that Fredo is the family traitor he had been looking for. Despite twice telling Michael that he had never met Ola, Fredo drunkenly lets slip that they had met in Havana earlier that year.
When Sonny brings Tom home and demands he be taken in, the Corleone family welcome him as a family member. Hagen considers Vito his true father, although Vito never formally adopts him, believing it would be disrespectful to Hagen's deceased parents.
Michael's Safety: Vito deeply cared for Michael and wanted to shield him from the dangers and violence of the criminal world. He recognized Michael's potential for leadership and, therefore, did not want Michael to be directly involved in acts of vengeance, which could put him in harm's way.
As Fredo prays the Hail Mary (which he claimed brought him luck whilst fishing), Neri shoots him in the back of the head, not knowing that Anthony was watching from his bedroom window.
