A spokesman for the Attorney General said that Mr. Spitzer's office was continuing a criminal investigation into whether individuals at the hospital or its subcontractors committed billing fraud.

There is also a Federal investigation into billing fraud at the Columbia/HCA Corporation, a hospital chain that Mr. Rainwater helped found.

He has said he supported universal coverage paid for by savings derived from Government-imposed cost controls and efforts to reduce billing fraud.

A carrier's profit is significantly impacted by billing fraud.

Investigators are also examining allegations that Columbia engaged in "upcoding" - reporting that a diagnosis was more severe than what was treated - and in potential billing fraud at hospital labs.

Add to the troubles some complaints that affect all hospitals: expenses to prepare their computers for 2000, problems getting insurance companies and the Government to pay up, and new efforts to defend against accusations of billing fraud.

In 2004, allegations of billing fraud were made against the company when an office administrator reported Hanger employees in New York for forging false prescriptions for non existent patients.

As examples of billing fraud, the affidavit cites instances in which blood tests were billed for that were never ordered or not medically needed.

Mr. Weiss said that at a time when billing fraud was increasing, he was concerned that programs like Medicare have reduced spending on efforts to oversee payments.

She has collected scores of examples of lawyers, many with fancy résumés, who have been jailed or disbarred for billing fraud.