This segment was originally broadcast on Jan. 6, 2008. It was updated on July 25, 2008.
There are few men alive today with the underworld credentials of John Martorano, and even fewer who are out of prison and walking the streets. For more than a decade, Martorano was the chief executioner for Boston's Winter Hill Gang, a loose confederation of Irish and Italian-American gangsters run by James "Whitey" Bulger.
Martorano, a former Catholic altar boy and high school football star, became a cool and calculating killer. But as correspondent Steve Kroft first reported in January, he is perhaps best known as the government witness who helped expose a web of corruption and collusion involving the mob and the Boston office of the FBI.
For years, he was one of the most feared men in Boston, and this is why: Martorano says he never kept count of how many people he killed. "Until in the end, I never realized it was that many," he tells Kroft.
Asked how many, Martorano says, "A lot. Too many."
"Do you have a number?" Kroft asks.
"I confessed to 20 in court," Martorano replies.
"You sure you remembered 'em all?" Kroft asks.
"I hope so," Martorano says,
Martorano had to remember them all. It was part of a deal he cut with the federal government that put him back on the streets of Boston after only 12 years in prison -- a little more than seven months served for each of the 20 people he killed, many of them fellow gangsters, and many of them at close range after looking into their eyes.
Asked if he always killed people by shooting them, Martorano tells Kroft, "I think I stabbed one guy."
"But you like guns," Kroft remarks.
"Well, it's the easiest way I think," Martorano says.
Martorano says he did not get any satisfaction out of the fact that people were afraid of him. "But everybody likes to be respected for one thing or another," he admits.
His manner is unemotional and detached, and he speaks with the brevity of a professional witness, which he has become. His testimony helped wipe out one of the largest criminal enterprises in New England, for which he served as chief executioner. But Martorano is no psychopath, and he doesn't much like the term "hit man."
"The hit man is…that sounds to me like somebody that's getting paid to a paid contract. I mean, you could never pay me to kill anybody," he says.
"A lot of people would say you're a serial killer," Kroft remarks.
"I might be a vigilante, but not a serial killer," Martorano says. "Serial killers, you have to stop them. They'll never stop. And they enjoy it. I never enjoyed it. I don't enjoy risking my life but if the cause was right I would."
Martorano says he "always" felt like he was doing the right thing. "Even if it was wrong, I always tried to do the right thing."
If you believe Martorano -- and the Justice Department does -- he killed out of a sense of loyalty and duty. He sees himself as a stand-up guy, a man of his word, which is why he decided to talk to 60 Minutes.
It goes back 50 years, when Martorano was a star running back on the Mount St. Charles Academy football team in Rhode Island. One of his blockers was the late 60 Minutes correspondent Ed Bradley.
He promised Bradley he would sit down with him and tell his story, but Bradley died unexpectedly before Martorano got out of prison.
"I never thought I'd be sitting here with you, I thought I'd be here with Ed. But I'm sitting here because Ed wanted me to sit here and I'm honoring that," Martorano explains.
"I know one of the questions that Ed wanted to ask you. In sort of the way that Ed asked those questions, I think he wanted to be sitting here and say, 'What happened Johnny?' Why was it do you think that you went in different directions?" Kroft asks.
"Well, I think it was mainly the influence of my father and his principles and his values that he pushed onto me," Martorano explains.
His father owned an after hours club called Luigi's in a rough Boston neighborhood known as the "Combat Zone." It was a hangout for hoodlums who would become Martorano's role models, and many of them shared his father's simple Sicilian values.
"He was the oldest son, and he taught me 'You're the oldest son and this is your heritage. You've got to take care of your family and be a man. I don't care what else you are, you've got to be a man,'" Martorano says.