William Bulger (searchtold a congressional panel Thursday he has no idea where his fugitive mobster brother is and never told him to remain on the lam, even as he became convinced the FBI wanted him dead.

For years, congressional investigators, the media and the public had wondered what Bulger thought of his brother, mobster James "Whitey" Bulger (search), who has been implicated in nearly two dozen murders.

But Bulger -- a longtime political force in the state before he became head of the University of Massachusetts -- shed no light on his brother's whereabouts, and said there's little he could've done to steer him from a life of crime.

"I was unable to penetrate the secretive life of my older brother," Bulger told members of the House Government Reform Committee (search). "Jim had his own ways I could not possibly influence."

Bulger said he had a brief telephone conversation with Whitey after he fled to avoid prosecution in 1995. But, he said, they never discussed whether Whitey should turn himself in, and he never advised him to stay away.

In subsequent years, he came to believe the FBI was looking for harm to come to Whitey -- especially after the media was leaked the news that Whitey had been an FBI informant.

Committee members are seeking to get to the bottom of the FBI's handling of its mob informants, whether agents had tipped off Whitey that he was about to be indicted, and whether William Bulger knows his brother's whereabouts.

At least one congressman said just before Bulger began his testimony that others who knew of FBI and mob misdeeds remained silent out of fear.

"People could not bring themselves to speak the truth. Now we know why: They were scared, they were terrified," said Rep. Dan Burton, R-Ind., who started the investigation into the FBI two years ago.

Breaking an eight-year public silence about his relationship with his brother, Bulger, a former state Senate president, focused on how little he knew about the "difficult and painful subject" of his brother's life and the pain he felt for those who have been affected.

He offered little insight into what committee leaders said was their key area of interest: corruption in the way the FBI uses informants.

Whitey Bulger was a high-level FBI informant in Boston and is now on the agency's "Ten Most Wanted" (search) list. He is linked to 21 murders. He fled in 1995, just before federal indictments were issued and after he was tipped off by his FBI handler.

"I know my brother stands accused of many things ... serious crimes, brutal crimes," Bulger said. "I am mindful of the victims in this matter, and I do not have the words that are adequate to let them know of my anguish."

William Bulger's testimony comes two months after the committee granted him immunity from prosecution. In December he was called before the panel, but invoked his Fifth Amendment rights and refused to answer questions.

That refusal inflamed political opponents, including Republican Gov. Mitt Romney (search), who called on him to resign. Romney also tried to eliminate his university position.

Bulger acknowledged that furor in his remarks Thursday, noting that a political foe claimed he chose "my brother over my civic duties and my public responsibilities. There is no basis in fact for such an assertion."

And while he professed to be candid with the panel, he testified knowing that if he contradicted anything he told a grand jury in 2001, he could be charged with perjury.

Committee members on Wednesday said their goal was not to "get" Bulger.

"He has a very distinguished career and nobody is trying to get him in trouble," said Rep. Tom Davis, R-Va., the committee's chairman.

He warned, however, that the immunity would not protect Bulger if he lied to Congress.

Lawmakers posed many questions about whether Bulger used his influence as Senate president to help his brother. They said they wanted to know if he got involved when Whitey Bulger was arrested at an airport trying to carry $500,000 onto a plane.

And they want to know if he used his Senate position to quash a federal investigation into a real estate development project known as 75 State Street. The FBI agent in charge of that investigation reportedly worked closely with Whitey Bulger when he was an informant.