One of James "Whitey" Bulger's closest associates implicated the crime boss Tuesday in a string of murders connected to their gang's failed effort to skim hundreds of thousands of dollars from the gambling businesses once operated by the World Jai Alai company in Florida and Connecticut.

At one point in the conspiracy, with the skim doomed and Bulger's Winter Hill Gang the subject for the first time of serious law enforcement attention, the associate — gang hit man John Martorano — said that Bulger pressed him to kill one of his best friends as part of a cover-up. Martorano said he agreed because Bulger had learned from a corrupt FBI agent that the friend was likely to talk.

"How did you feel about that? " Assistant U.S. Attorney Fred Wyshak asked.

"Very bad," Martorano replied.

For years, the murders tied to the jai alai industry were one of Connecticut's most stubborn crime mysteries. The state became the first to legalize gambling on the fast-paced Basque sport in the late 1970s, when World Jai Alai tried to expand beyond its base in Florida. Thirty years ago, Connecticut was home to three jai alai gambling venues called frontons.

Martorano's account of the murders came during his second day as a key government witness at Bulger's racketeering trial. Bulger is accused of 19 killings — four of them tied to jai alai — and other crimes that date to the 1970s.

Most of Martorano's testimony has been a terse and emotionally flat recitation of the details of violent death, illustrated by prosecutors with grainy projections of 35-year-old crime scene Polaroids.

But the pace slowed Tuesday when prosecutors questioned Martorano about events beginning in 1981, when, he said, former World Jai Alai President John B. Callahan approached the leaders of the Winter Hill Gang — then Bulger, Martorano and Stephen "the Rifleman" Flemmi — with a plan to take over the business by force.

Roger Wheeler, a millionaire industrialist in Tulsa, Okla., had just bought the company. Callahan, a Boston native, had been forced to resign as its president after state police detectives in Connecticut, where he had applied for a gambling license, found him socializing at Boston night spots such as the Playboy Club with Martorano's brother and other members of the Winter Hill Gang.

"He was a high priced accountant days," Martorano testified. "And put on a leather jacket and wanted to hang out with rogues at night."

"Did you ever hear the phrase 'Wannabe gangster?'" Wyshak asked.

"That's what he was," Martorano said.

When Callahan was company president, his drinking buddies in the Boston underworld began showing up in management positions. Martorano testified Tuesday that Callahan told him in the early 1980s that the new owner, Wheeler, had begun an internal investigation based on suspicion that someone had been stealing from the business. Callahan was afraid he would end up in jail.

Martorano said Callahan's solution, at least initially, was to buy the business from Wheeler.

"He had the financing," Martorano said. "He figured that would stop the investigation."

But Wheeler refused to sell, Martorano said, and Callahan decided to hire the Winter Hill Gang to kill him.

Martorano said Callahan made the decision after consulting with H. Paul Rico, a retired Boston FBI agent with ties to Flemmi and other members of the Winter Hill Gang. Callahan had hired him as World's head of security and Wheeler had retained him. Martorano said Rico persuaded Callahan that, with Wheeler out of the way, his widow could be persuaded to sell.

"Callahan wanted to get Mr. Wheeler killed so he wouldn't get in trouble" Martorano testified. "He said that he discussed it with Paul Rico. If Roger Wheeler wasn't on the scene, they could put the proposal to his wife."

The gang's payoff would be a skim of $10,000 or so a week from World Jai Alai's cash concessions, such as parking and food, Martorano testified. Under Callahan's plan, Martorano said, Callahan would take back control of the business. The Winter Hill Gang, in return for the skim, would prevent other criminal groups from trying to push their way in.

"He didn't think that the mafia would bother him if we were with him," Martorano testified.