Lawmakers on Wednesday voted to give University of Massachusetts President William Bulger and New England mob boss Francis Salemme immunity from prosecution in exchange for their testimony on the Boston FBI and its ties to mob informants.

"This information will help the committee gain a complete understanding of the scope of the FBI's misuse of informants in Boston," said House Government Reform Committee Chairman Tom Davis, R-Va.

For eight years, Bulger has remained silent about his fugitive mobster brother, his possible whereabouts and his ties to the FBI.

Now political and legal observers say Bulger has some incentives to start talking: a grant of immunity from prosecution by the committee and flak he's caught back home for clamming up about his brother.

"It will be very interesting to see what he has to say," said Boston lawyer Jeffrey Denner. "His reputation has suffered greatly here."

The panel voted 30-1 to grant immunity to Bulger and 34-0 to grant immunity to Salemme Wednesday morning. Rep. Steven LaTourette, R-Ohio, cast the only dissenting vote, saying Bulger has withheld information about his brother and should be investigated further by the Justice Department.

"It was expected and it's another step along the way," Bulger said in Boston. "Things have been going along in a pretty cooperative fashion and so we'll do whatever is expected of us next."

Asked what he would tell the committee, Bulger replied: "I have no idea what they they'll be asking."

Neither Bulger nor Salemme attended the hearing. No date has been set for their testimony, but Davis it will happen "as quickly as we can."

The Justice Department has signed off on immunity.

Lawmakers are hoping Bulger, 68, will provide information about whether FBI agents obstructed homicide cases to protect his brother, James "Whitey" Bulger, a bureau informant linked to 21 murders. Whitey Bulger fled in 1995 when he learned he was about to be indicted.

Last December, William Bulger, a longtime president of the Massachusetts state Senate, appeared at a Congressional hearing and invoked his Fifth Amendment right to not incriminate himself. He also appeared before a grand jury and later told reporters: "I don't feel an obligation to help everyone to catch him." Bulger's silence was roundly criticized by Massachusetts Gov. Mitt Romney.

"This immunity will take away Billy Bulger's last excuse to not tell the committee what he knows about his brother's activities with the FBI," committee vice chairman Christopher Shays, R-Conn, said Tuesday. "We're giving two people immunity and the expectation is that both have information that will be helpful to the committee in exposing what happened."

Gerard O'Neill, who wrote a book on the Boston mob, said William Bulger should have information about his brother's relationship with the FBI. And by testifying, he said, William Bulger "pulls the rug out from under those who would say he can't take the Fifth and still stay president of the University of Massachusetts."

Rep. John Tierney, D-Mass., a committee member, said if William Bulger has substantive information, "then there is no reason not to go ahead with the immunity."

William Bulger would not comment on the proceedings. His spokesman, Robert Connolly, has said the university president is ready to testify, and the immunity will "make it much more comfortable for him to answer the questions they have."

Connolly denied that his boss' reputation was sullied when he refused to testify, saying people make a distinction between William Bulger and "the family situation that has been a source of anguish."

But he acknowledged, "There will be value in some closure being reached on this issue."

While Bulger's testimony will be new, Salemme, 69 -- a mob associate of Whitey Bulger -- already has been interviewed by committee staff.