The case against GOP uber-lobbyist Jack Abramoff seems to expand every day. Now investigators are going back three years to a case in which a federal prosecutor was pulled off his investigation into Abramoff, just as it was reaching a crucial juncture:

The Justice Department’s inspector general and the F.B.I. are looking into the demotion of a veteran federal prosecutor whose reassignment nearly three years ago shut down a criminal investigation of the Washington lobbyist Jack Abramoff, current and former department officials report.

They said investigators had questioned whether the demotion of the prosecutor, Frederick A. Black, in November 2002 was related to his alert to Justice Department officials days earlier that he was investigating Mr. Abramoff. The lobbyist is a major Republican Party fund-raiser and a close friend of several Congressional leaders.

Colleagues said the demotion of Mr. Black, the acting United States attorney in Guam, and a subsequent order barring him from pursuing public corruption cases brought an end to his inquiry into Mr. Abramoff’s lobbying work for some Guam judges…

The announcement [that he was being replaced] came only days after Mr. Black had notified the department’s public integrity division in Washington, by telephone and e-mail communication, that he had opened a criminal investigation into Mr. Abramoff’s lobbying activities for the Guam judges, the colleague said. The judges had sought Mr. Abramoff’s help in blocking a bill in Congress to restructure the island’s courts.

The colleagues said that Mr. Black was also surprised when his newly arrived bosses in Guam blocked him from involvement in public corruption cases in 2003. Justice Department officials said Mr. Black was asked instead to focus on terrorism investigations, which had taken on new emphasis after the Sept. 11 attacks.

“Whatever the motivation in replacing Fred, his demotion meant that the investigation of Abramoff died,” said a former colleague in Guam.

Connect: