Democratic senators on Thursday pressed for a criminal fraud investigation of the Bush administration's hiring of a commentator to promote its agenda.

Congressional auditors concluded last week that the Education Department engaged in illegal "covert propaganda" by hiring Armstrong Williams (search) to endorse the No Child Left Behind Act without requiring him to disclose he was paid.

That review by the Government Accountability Office did not come with any penalty.

In a letter to Attorney General Alberto Gonzales, Sens. Frank Lautenberg, D-N.J., and Edward Kennedy, D-Mass., said questions of fraud remain for the department and for Williams.

The department paid Williams, a commentator with newspaper, television and radio audiences, to produce ads promoting Bush's law. Work orders show he also was to provide media time to department officials and persuade other blacks in the media to discuss the law.

Yet the department provided the GAO with almost no evidence of the work that Williams cited in his monthly reports. In their own search, GAO auditors either could not find the work Williams listed or could not connect the work they found to his contract.

"Taking taxpayer dollars for work you didn't do is fraud -- period," Lautenberg said. "Americans are already upset that Bush administration paid off a columnist to write glowing reviews of the president's education agenda. The notion that he may not have even done the work is even worse."

Sens. Byron Dorgan, D-N.D., and John Kerry, D-Mass., also signed the letter to Gonzales.

The Education Department had no comment.

Shirley Dave, a spokeswoman for Williams, said he is negotiating with department officials to return part of the public money he was paid. She declined no comment on the request for a criminal review.

The department was to pay $240,000 to Williams, a subcontractor in a $1.3 million contract the agency had with Ketchum, a public relations firm. The department has paid $186,000 to Ketchum for the work Williams was hired to perform, the GAO found.

The deal occurred during the tenure of Education Secretary Rod Paige (search). His replacement, Education Secretary Margaret Spellings (search), has pledged stricter oversight of agency spending.

After the GAO said the hiring of Williams amounted to propaganda, department spokeswoman Susan Aspey said, "We've said for the past six months that this was stupid, wrong and ill-advised."

The department's inspector general found that the administration's hiring of Williams was not illegal or unethical, but was a poor decision that continued even after concerns were raised to the White House. At the time of the Williams' contract, Gonzales was White House counsel.