It was not until last August that the department finally corrected these wildly overblown figures. In a blinding acknowledgment of the obvious, the inspector general concluded: “We believe the department should have been more forthright at a much earlier date about this flawed information.”

Adam J. Levitin, a professor at the Georgetown University Law School, said the report was troubling not only because of what it revealed about past cases, but also because it suggests that there will be few consequences for those who commit financial fraud in the future.

“The I.G. report confirmed what’s been clear for quite a while — that the D.O.J. has never taken mortgage fraud seriously,” Professor Levitin said. “There is going to be no comeuppance for crimes committed during the financial crisis. This sets a really bad precedent for future crises because we’re seeing that there is going to be no deterrent effect of criminal law.”

After reading the report, I asked Mr. Breuer, now the vice chairman of the law firm Covington & Burling in Washington, to square his public comments about the agency’s aggressive pursuit of cases with the conclusions in the inspector general report. A spokeswoman said he declined to comment.

Then I called Edward E. Kaufman, the former senator from Delaware who had tried unsuccessfully to get the Justice Department to move aggressively on financial-crisis cases. He convened two sets of congressional hearings on financial fraud cases in 2009 and 2010 and repeatedly questioned department officials about their efforts.

Mr. Kaufman, a Democrat who retired from the Senate in 2010, is now a visiting professor at the Duke University School of Law and a weekly columnist for The News Journal, a newspaper in Wilmington, Del. He said he was discouraged but not surprised by the report. “There was a lot of talk at the time, but fraud enforcement was never a priority in the Justice Department,” Mr. Kaufman said. “Not only was this not their top priority, it was their last priority.”

Oddly, the report gives the Justice Department a pass on its failure to prosecute Wall Street banks and other entities for securities fraud related to the mortgage debacle. “The F.B.I. considers this type of misconduct to be a form of securities fraud and not mortgage fraud; therefore, we did not include as part of the scope of this audit,” it said.