- "I'm here. You were right, it was Malone. There's a dead FBI agent here and he pulled the trigger."
- ―Jimmy DeNunzio to Michael Corleone[src]
- "Jeez, Monk a traitor? I'd never a' guessed..."
- ―Jimmy DeNunzio[src]
After Malone killed an FBI Agent who had informed for the family, DeNunzio arrived, under the pretense that he had been late and was planning to help the two men out. Monk left angrily, and DeNunzio called Michael, who informed Trapani of the situation and ordered him to eliminate his friend. DeNunzio, still surprised that Malone could have been a traitor, informed Trapani that Malone would be at the Va Va Voom Room. He was last seen at Trapani's initiation as Don at the original Corleone mall.
When Aldo Trapani became the Don of New York in 1955, Jimmy became one of his caporegimes and led Tessio's regime in Brooklyn. After Trapani was killed in Cuba in 1959, it is possible that DeNunzio became one of Dominic's men or was killed by the Rosato Brothers. Another possibility for DeNunzio after Aldo's death is that he could have became one of Frank Pentangeli's men in his branch of the family.