Alleged Boston mob kingpin James Whitey Bulger's lawyer JW Carney has offered a novel defense of his client this week.

According to AP, Bulger's lawyer claimed his client would have never cooperated with the FBI as an informant because he is of Irish descent, 'and the worst thing an Irish person can do is become an informant.'

'Ask yourself. Would an informant be paying tens of thousands of dollars to the agent? Wouldn’t it be the other way around?' Carney said.

The 83-year-old Irish American is reportedly accused of 19 murders, extortion, money laundering and arms trafficking, but reports that he served as an informer have raised questions about why it took federal investigators so long to track him down. Bulger was arrested in June 2011 after 16 years on the run.

'It’s a case about organized crime, public corruption and all sorts of illegal activities,' prosecutor Brian Kelly told the court this week. 'And at the center of all this murder and mayhem is one man,” who led “a group of criminals who ran amok in the city of Boston for 30 years.'

Kelly described the Irish-American Bulger as a crime godfather in Boston's underworld, one who would not hesitate to strangle, shoot, kill or maim anyone he saw as a rival, informer or witness to his criminal activities.

Bulger 'made millions extorting people' and 'a ton of money selling drugs, especially cocaine,' Kelly said, adding that Bulger served as an FBI informant from 1975 to 1990, helping to shut down two other crime groups that rivaled his own Winter Hill Gang.

Bulger reportedly watched the court proceedings in silence. The trial is expected to last into September.

‘Whitey’ Bulger arriving home to BostonStuart Cahill