He started to dominate the organized crime world. To increase his earnings, he partnered with mobster Roy DeMeo, who was running a stolen car ring in the Brooklyn neighborhoods of Flatlands and Canarsie. DeMeo had connections with the Lucchese crime family and a reputation as a capable and resourceful earner. Gaggi persuaded DeMeo to leave the Luccheses and work instead for the Gambinos. Gaggi and DeMeo began making co-loans to loan shark customers. By 1970, DeMeo was officially working for Gaggi and paying him weekly tributes. In 1972, the two men forced their way into a partnership with a company that illegally processed X-rated films. After law enforcement raided the company in 1973, owner Paul Rothenberg began to cooperate with them. Gaggi ordered DeMeo to murder Rothenberg, whose body was found with bullet wounds shortly thereafter. The Rothenberg killing was the first of many murders committed by DeMeo's crew. While Gaggi was not involved in most of these killings, he did participate in some of them. DeMeo and Gaggi shot and killed Vincent Governara, a young man with no mob ties, over a fight between him and Gaggi that had occurred twelve years before. In 1976, DeMeo killed George Byrum, an electrical contractor, who had tipped off thieves who attempted to burglarize Gaggi's Florida vacation home without knowing Gaggi and his wife were present. Under Gaggi's direction, DeMeo shot and killed Byrum in a Miami hotel room while Gaggi and another mobster, Tony Plate, attempted to dismember the body. However, they were interrupted by a construction crew outside the room that was repairing a faulty air conditioning unit, causing them to flee. The bloody corpse of George Byrum was later found by the motel maid. In late 1976, boss Carlo Gambino died of natural causes. Before his death, he had designated Paul Castellano, his brother-in-law and head of the family's Brooklyn faction, as the new boss. However, the Manhattan faction favored Dellacroce. At a leadership meeting held at Gaggi's house, it was agreed that Castellano would become the new Gambino boss while Dellacroce was retained as underboss. Gaggi was promoted to "capo" of Castellano's old crew. Gaggi remained close to Castellano, hoping to become promoted to underboss.