University of Massachusetts president William Bulger will be subpoenaed to testify about his fugitive crime boss brother after refusing requests to appear voluntarily, an official said Saturday.

James Wilson, head lawyer for the House Government Reform Committee, said Bulger's lawyer, Thomas Kiley, told him his client would not show up at a Friday hearing in Boston.

"Because Mr. Kiley was so emphatic in his message that Mr. Bulger will not appear, we started our process to issue a subpoena," Wilson told The Associated Press.

The congressional committee chaired by Dan Burton, R-Indiana, is investigating how the Boston FBI became corrupted during a decades-long practice of using mobsters as informants, including Bulger's brother, James "Whitey" Bulger.

James Bulger, 73, fled in 1995 just before he was indicted on racketeering and extortion charges. He has since been indicted on additional charges related to 18 murders, and is on the FBI's Ten Most Wanted list.

William Bulger, 68, the former state Senate president and one of Massachusetts's most high-profile public figures, rarely discusses his relationship with his brother. Kiley refused to comment when reached Saturday.

The committee originally scheduled Bulger to testify Thursday. Several days later, it added a second day of testimony, on Friday, and scheduled Bulger as the lone witness.

The request for a subpoena will be sent to the clerk of the U.S. House to be certified Monday morning, Wilson said.

Wilson would not say what the panel will ask Bulger, who risks imprisonment if he doesn't appear. Bulger is expected to be questioned about is what, if any, influence he had with law enforcement while his brother was an informant.

The hearings are part of a series of hearings being held by Burton's panel, which is looking at the entire Justice Department's handling of mob informants. The committee is investigating the relationship between Boston FBI agents and the hit men and mob leaders they used as informants, and sometimes protected from prosecution for crimes as serious as murder.

Documents released to the committee indicated that FBI headquarters in Washington D.C. were aware of such relationships.

During the trial earlier this year of retired FBI agent John Connolly, confessed hit man Joseph Martorano testified that William Bulger asked the FBI to protect his brother.

Martorano testified that when Connolly asked William Bulger what he could do for him, the reply was: "Just keep my brother out of trouble."

Bulger has denied that claim. He has publicly discussed his brother on only a handful of occasions, including a few paragraphs in his autobiography.