John Martorano 2008.jpg

John Martorano is questioned about his plea agreement in exchange for testifying against former FBI agent John Connolly in the Miami Courthouse in 2008. Martorano, who served 12 years in prison after a plea deal, and who has admitted killing 20 people, testified Monday at the trial of James "Whitey" Bulger in federal court in Boston.

(Marice Cohn Band / Associated Press file)

BOSTON (AP) — Former hitman John Martorano has described more killings as he testifies for a second day in the racketeering trial of James "Whitey" Bulger in Boston.

On Tuesday, Martorano gave chilling details about murders he committed after they were ordered by Bulger and his partner, Stephen "The Rifleman" Flemmi. He also described a 1975 killing he said Bulger and Flemmi did themselves.

Martorano said Bulger and Flemmi shot Edward Connors in a phone booth because they were afraid he would tie them to the 1973 killing of a Bulger rival.

Martorano served 12 years in prison after admitted killing 20 people. Twelve of those people were killed while Martorano was working with Bulger and Flemmi.

The 83-year-old Bulger is charged in a racketeering indictment with participating in 19 killings.

THIS IS BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.

Former hitman John Martorano who admitted killing 20 people was set to testify for a second day in the racketeering trial of James "Whitey" Bulger, as Bulger's attorneys prepared to attack his credibility.

Martarano took the stand Monday to testify against Bulger, a man to whom he was once so close he named his youngest son after him.

He said he was heartbroken when he learned in the late 1990s that Bulger and partner Stephen "The Rifleman" Flemmi had been working as FBI informants. That's when he decided to cooperate with prosecutors and testify against Bulger and others in exchange for a reduced sentence, he said.

Bulger's lawyers did not get a chance to question Martorano on Monday, but they are expected to challenge his credibility and the deal he got from prosecutors when they cross-examine him, possibly as early as Tuesday. Martorano served just 12 years in prison after admitting to the 20 murders. He was released in 2007.

In opening statements last week, Bulger's lead attorney, J.W. Carney Jr., told the jury that prosecutors were so desperate to get Martorano to testify that "they basically threw their hands up in the air and said, 'Take anything you want.'"

Bulger, now 83, is charged in a broad racketeering indictment that accuses him of participating in 19 murders in the 1970s and '80s.

Martorano spoke nonchalantly Monday when describing a string of murders he committed while he was a member of the notorious Winter Hill Gang in the '70s.

But he said he felt betrayed when he learned his former partners — Bulger and Stephen "The Rifleman" Flemmi — were FBI informants.

"After I heard that they were informants, it sort of broke my heart, said Martorano.

Martorano is the first of three former Bulger cohorts who have cooperated with prosecutors and agreed to testify against Bulger.

"They were my partners in crime, they were my best friends, they were my children's godfathers," Martorano said, of Bulger and Flemmi. He said he named his youngest son James Stephen after them.

During his testimony, Martorano described what he said was Bulger's involvement in several killings, saying that while he shot someone from a car, Bulger and others would ride in a second car to intervene if anyone tried to stop the shooting.

He described the death of one victim, Alfred Notarangeli, in 1974.

Martorano said Bulger's gang decided to kill Notarangeli to help the Italian Mafia in Boston, a sometime rival, whose leadership said Notarangeli had killed one of their agents and was a "loose cannon."

On March 8, 1973, Martorano said, he drove in the lead car while Bulger followed, both tailing a Mercedes they believed was driven by Notarangeli.

"We pulled guns and we were shooting at it," Martorano said, referring to himself and another member of the gang.

They later learned that it was not Notarangeli in the car, but instead a man named Michael Milano, who was shot to death. Martarano said they continued to chase Notarangeli and ended up killing him and his brother, Joseph Notarangeli.

Bulger is charged in the killings of both brothers, as well as Milano's killing.