Of the cases, 1,842 involved more than $1 million in losses. As of November, federal charges related to mortgage fraud were pending against 826 defendants.

Lanny A. Breuer, the assistant attorney general for the Justice Department’s criminal division, said prosecutors were focused not only on lenders that underwrote risky mortgages, but also on companies that packaged and sold the mortgages to investors.

“We absolutely are looking at the conduct of the securitizers themselves, and what did they say to those who purchased the securitizations; and what did they say about the underlying conduct,” Mr. Breuer said.

But several state officials told the panel that federal action had come too late  a point made by the commission’s chairman, Phil Angelides, who said the head of the F.B.I.’s criminal division had warned in 2004 of an “epidemic” of mortgage fraud that, if unchecked, could match the savings-and-loan crisis of the 1980s in magnitude.

“In the years preceding the crisis, federal regulators often showed no interest in exercising their regulatory authority, or worse, actively hampered state authority,” Lisa Madigan, the Illinois attorney general, told the commission.

The Federal Reserve failed to tighten underwriting standards, while the Office of the Comptroller of the Currency and the Office of Thrift Supervision were “actively engaged in a campaign to thwart state efforts to avert the coming crisis,” she said.

John W. Suthers, the Colorado attorney general, described the fallout from the housing crisis. He spoke of “a dramatic shift in consumer complaints” in the last two years.