Karla W. Corcoran, the U.S. Postal Service inspector general, retired yesterday after a federal investigation found that she abused her authority, wasted public money and promoted questionable personnel practices.

The Postal Service's Board of Governors announced that David C. Williams, a former IG at four different agencies, would immediately take over as only the second inspector general in the history of the agency.

The investigation by the President's Council on Integrity and Efficiency found that Corcoran "followed a pattern and practice of unprofessional conduct in the management of the USPS OIG, used questionable judgment in areas within her discretion, extravagantly expended USPS funds, and engaged in personnel practices which were either questionable or not in accord with USPS policy," wrote Grant D. Ashley, chairman of the council's integrity committee.

The committee recommended that "the most severe administrative sanctions available be taken against Ms. Corcoran," Ashley wrote in a July 28 report cover letter to Clay Johnson III, council chairman and deputy director for management at the Office of Management and Budget. The council promotes professionalism among IGs and in U.S. agencies.

In a telephone interview yesterday, Corcoran used an expletive to characterize the findings of the council's 274-page report and said she had been made a scapegoat.

"They did not employ people that were familiar with postal operations," Corcoran said of investigators. "It's as much of an attack on the Postal Service itself as it is on me. They don't like a lot of postal practices, and so I became the catalyst."

Corcoran, who earned $142,500 a year, became the Postal Service's first IG after Congress created the office in 1996 to combat the perception that the chief postal inspector could not be objective. Corcoran's job was to root out waste and fraud at the Postal Service, which has 750,000 employees and a $65 billion budget. She said she identified $2.2 billion in potential and actual savings during her tenure. But critics, including a group of 55 current and former employees, complained of what they described as her overbearing, "values-oriented" management style, reckless spending and unfair personnel decisions.

Investigators found that Corcoran had spent more than $1 million for each of the agency's three most recent annual recognition conferences, events in which all 750 employees of the IG's office gathered at D.C. hotels for team-building drills, training and awards ceremonies. Investigators said she humiliated employees by yelling at them in public; promoted some without relevant experience; and left threatening messages with former staffers to try to hinder the probe.

The Postal Service said in a written statement that Corcoran departs "with the thanks of the governors for her service."

Senate Finance Committee Chairman Charles E. Grassley (R-Iowa) said an IG must be "above reproach," and that Corcoran was not.

"The U.S. Postal Service . . . touches the lives of nearly each American every day," said Grassley, whose own probe of Corcoran's tenure produced similar findings. "Someone must be making sure that taxpayers' money is invested wisely."

Staff researcher Lucy Shackelford contributed to this article.

Karla W. Corcoran says she is a scapegoat for the Postal Service.