Whitey Bulger Trial: Admitted killer John Martorano insists he told the truth in implicating reputed mob boss

(AP) BOSTON - An ex-hit man who admitted killing 20 people insisted Wednesday that he told authorities the truth when he implicated reputed mob boss James "Whitey" Bulger in 11 of the slayings, but he acknowledged lying in the past, including to his close friend just before he shot him in the head.

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VIDEO: The Executioner: John Martorano speaks with 60 Minutes

John Martorano is one of three former Bulger loyalists who agreed to cooperate with prosecutors and testify against Bulger at his racketeering trial. Bulger, the reputed former head of the mostly Irish-American Winter Hill Gang based in South Boston, is accused of playing a role in 19 killings during the 1970s and '80s.

On Wednesday, Martorano's third day on the witness stand, he endured a stinging cross-examination by Bulger attorney Hank Brennan, who repeatedly challenged his truthfulness and his motives in testifying against Bulger.

Martorano insisted that he told prosecutors the truth about the role of Bulger and his partner, Stephen "The Rifleman" Flemmi, in various killings, but Brennan suggested that Martorano was a chronic liar who fabricated or exaggerated Bulger's involvement so he could get a reduced sentence for his own crimes.

Martorano served 12 years in prison after he cut a deal with prosecutors and agreed to testify against Bulger.

Brennan brought up the 1982 killing of John Callahan, a Boston businessman who Martorano described as a close friend.

"You even lied to your best friend Jon Callahan before you murdered him," Brennan said.

"Correct," Martorano replied.

"To me that was a necessity," the ex-hit man said. "I couldn't tell him I wanted to shoot him."

Brennan also pointed out inconsistencies between what Martorano told investigators in the late 1990s and what he told jurors in Bulger's trial this week.

Martorano acknowledged that he originally told investigators that Flemmi was sitting next to him in a car and fired shots at James "Spike" O'Toole as he stood behind a mailbox on Dec. 1, 1973. O'Toole was killed because he had shot and wounded Flemmi's brother.

Flemmi was a fugitive hiding in Montreal at the time of the shooting.

"It was somebody else in the back seat, not Flemmi," he said. "I was in error and corrected it."

Jurors were shown photos of the mailbox riddled with bullets, as well as images from seven other killings, showing shot-up cars with shattered glass and blood visible on the seats.

Assistant U.S. Attorney Fred Wyshak tried to rehabilitate Martorano in the eyes of jurors. Wyshak went through 11 murders and asked him if he and Bulger were involved in each. "Correct," Martorano replied each time.

Bulger, now 83, was one of the FBI's most wanted fugitives when he fled Boston in 1994 after being tipped to an upcoming indictment by former FBI Agent John Connolly. He was finally captured in Santa Monica, California, in 2011.

Prosecutors say Bulger was a longtime FBI informant who was protected by Connolly and other agents in the Boston office. Bulger's lawyers deny that he was an informant and say he paid FBI agents to warn him about investigations of him and his gang's illegal activities, including bookmaking, extortion and loan-sharking.

Complete coverage of the Whitey Bulger case on Crimesider