The Federal Bureau of Investigation on Tuesday officially called an end to the computer overhaul spurred by 9/11, admitting the failure cost millions and that a substitute will take three-and-a-half years to complete.

While the FBI and others have been hinting that the Virtual Case File system -- the third and last part of a half-billion dollar retooling of the agency's computer system -- was in trouble, on Tuesday Robert Mueller, the FBI's director, broke the news to Congress in testimony before the House.

"I am tremendously disappointed that we did not come through with Virtual Case File," Mueller was quoted as saying by the New York Times to the House appropriate panel responsible for the FBI's budget.

Virtual Case File, a $170 million effort to make it easier for agents to share information and a cornerstone of the Bureau's remodeling of its computer system to better deal with terrorism, will be largely replaced, said Mueller, by off-the-shelf software. The substitute overhaul, which will come in four phases, won't start for months, however, and will take about three-and-a-half years to complete.

Mueller said he could not give a price tag for the project at this point.

Rep. Frank Wolf (R-Va.), the chairman of the House Science-State-Justice-Commerce Appropriations subcommittee before which Mueller testified, announced that his staff was beginning a formal investigation into why the Virtual Case File project failed.

In a letter to Mueller, Wolf promised that his committee will examine "the FBI's contracting procedures and management practices related to VCF" and will "provide vigorous oversight of VCF until its successful completion."