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A federal judge has rejected accused mobster James "Whitey" Bulger's plan to argue before a jury that he could not be prosecuted for the 19 murders he is accused of due to an immunity agreement worked out with a now-deceased prosecutor.

"The government's motion to preclude Bulger from arguing his claim of immunity to the jury as a defense at trial... is allowed," U.S. District Court Judge Denise Casper wrote in a 31-page ruling, according to the Boston Globe. "The Court has determined that the issue of immunity is not an issue for the jury."

Casper was appointed to hear the Bulger case in March, after the court of appeals removed Judge Richard Stearns from the case due to his history as a federal prosecutor.


Bulger's lawyer, J.W. Carney Jr., had argued that former Assistant U.S. Attorney Jeremiah O’Sullivan, who died in 2009, gave Bulger immunity, but denied that Bulger acted as a government informant.

Prosecutors said there was no evidence to back up the immunity claim.

In March, Stearns ruled that no government official would have given Bulger "prospective immunity" that allowed him to commit future crimes without being prosecuted, something Stearns called a "license to kill."

Casper upheld Stearns' ruling that a judge should decide whether Bulger had immunity before the jury trial and that no valid immunity agreement would have allowed murder.

"Although Bulger contends that 'Judge Stearns' rulings on these issues were almost entirely adverse to the defendant,' ... an adverse ruling does not mean that the rulings were wrongly decided or were 'tinged with bias' as Bulger contends," Casper wrote.

The 83-year-old accused mobster is accused of committing or ordering 19 murders in the 1970s and 80s as leader of Boston's "Winter Hill" gang. He has pleaded not guilty to all charges and faces the possibility of life in prison if convicted in a trial set to begin next month.

Bulger spent 16 years on the run before being captured in 2011, living under an assumed name in Santa Monica, California.

His longtime girlfriend, Catherine Greig, is serving a nearly eight-year federal prison sentence after pleading guilty to helping Bulger evade arrest. Greig is appealing her sentence.

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