Updated

Lawyers for reputed Boston gangster James "Whitey" Bulger have asked a judge to order prosecutors to turn over the name of an informant they say could help them discredit an important witness.

The defense says the informant could help them challenge the truthfulness of Kevin Weeks, a longtime Bulger associate who is expected to be a key prosecution witness at Bulger's trial.

In court documents, Bulger's lawyers say the informant could contradict Weeks' past testimony about the proceeds from a $14.3 million winning lottery ticket he, Bulger and two others shared in 1991. A former FBI agent has said two informants said the lottery ticket was a money-laundering scheme.

Bulger's lawyers are in court Tuesday for a status conference.

The 83-year-old Bulger is accused of playing a role in 19 murders.