By all accounts, it was a deal with the devil.
John Martorano, who has admitted to killing 20 people, including two teenagers, has strolled into the federal courthouse in South Boston over the past two days a free man, part of an agreement he reached with federal prosecutors in exchange for his testimony about James “Whitey” Bulger and the gangster’s corrupt relationship with the FBI.
Tom Donahue, whose father, Michael, was an innocent bystander allegedly gunned down by Bulger in 1982, called the deal “an absolute joke.”
But lawyers and law enforcement officials, even if they despise Martorano, say the government’s deal with him was a necessary evil to expose the broader history of Bulger’s reign of terror, unsolved murders, and FBI corruption.
“They would never have gotten the truth without him,” said Anthony Cardinale, a Boston attorney who represented Mafia head Francis P. “Cadillac Frank” Salemme during the 1998 federal court hearings that exposed the secret relationship of Bulger and Stephen Flemmi with the FBI.
“It was a deal with the devil, but in the long run it was the best thing they could do to get to the truth,” Cardinale said.
Martorano, a 72-year-old father of five, has turned heads over the past two days in Bulger’s racketeering trial with his uncensored testimony as he has described the 20 killings, seemingly without emotion. He implicated Bulger in 11 of the killings when he began cooperating with authorities after Bulger and Flemmi were exposed as informants in 1998.
Serving as the backdrop of his testimony is the controversial deal that has allowed him to remain a free man.
Martorano was sentenced to only 14 years in prison, and served 12 of them, after pleading guilty to racketeering, extortion, and money laundering charges. He admitted to 20 murders, but none of his testimony could be used against him. He was released from prison in 2007.
In exchange, he agreed to testify about his former cohorts and their relationship with the FBI.
Michael Huff, a retired detective who investigated Robert Wheeler’s killing — committed by Martorano allegedly at Bulger’s urging — said the deal was the best scenario under the circumstances.
“Nobody likes somebody not being held accountable for their crimes, but this set of circumstances was one that I don’t think anybody’s ever seen before,” he said. “It was a complicated situation, and I think it’s very easy for people to Monday morning quarterback a situation where there was just this unheard of set of circumstances, the collusion between a couple of FBI agents and these killers.”
During questioning Monday, prosecutors pointed out that Martorano had only faced a sentence of about five years in prison for his original racketeering indictment, before he admitted to the murders. If he did not cooperate, he might have been free anyway.
Martorano’s cooperation also opened a floodgate for others to testify against Bulger and Flemmi, leading to charges of murder against Bulger, Flemmi, and Bulger’s FBI handler John J. Connolly Jr. Martorano believed that “you can’t rat on a rat,” as he has testified before in Miami.
Facing new charges, Flemmi ultimately pleaded guilty and agreed to cooperate to escape the death penalty. Connolly was sentenced to 40 years in prison for providing Bulger with information that led him to allegedly kill an informant.
And Martorano helped implicate other law enforcement officers including former FBI agent H. Paul Rico, who died before he could go to trial.
On Wednesday, Martorano is set to testify for the third day in Bulger’s trial.
“This was a cost-benefit decision made at the highest levels of the Department of Justice,” said attorney Martin Weinberg, who represented Martorano when he first challenged the charges, then agreed to make a deal with prosecutors.
“The decision was made that without Martorano’s testimony the FBI’s involvement in Boston crime, a matter of huge public importance, would not have been fully illuminated,” Weinberg said.
Bulger’s lawyers questioned Tuesday whether Martorano was seeking to save himself out of fear that Flemmi could turn and testify against him first. They also accused him of shaping his testimony to favor prosecutors.
The lawyers also asked Judge Denise Casper to give jurors a “cautionary instruction” that would allow them to consider a witness’s deal with prosecutors in assessing his or her credibility, which the judge indicated she would do.
Travis Andersen of the Globe staff contributed to this report. Milton J. Valencia can be reached at mvalencia@ globe.com.