(LEGAFI) -- U.S. Department of Justice officials announced last week that two of the largest health care providers in Northern California have paid a combined $2.3 million to settle allegations that 61 of their hospitals double-billed Medicare for therapies and services.

Catholic Healthcare West (CHW) paid more than $875,000 and Sutter Health more than $1.43 million to settle allegations they submitted duplicate charges for infusion therapies and treatments to break up kidney and bladder stones.

The Medicare fraud settlement is a result of a year-long investigation by the Department of Health and Human Services that began with department auditors. The probe centered on six years of fraudulent Medicare billing at CHW from January 2002 to March 2008, and a four-year period at Sutter Health from September 2003 to December 2007.

Both companies admitted no wrongdoing in agreeing to the settlement, and no charges will be filed.

This is not the first time Sutter Health has been accused of double-billing Medicare, however.

Earlier this year, the state of California joined a 2009 whistleblower lawsuit alleging that Sutter Health routinely charged insurers for anesthesia services that were never performed and double-billed for services that were. The Sutter Health whistleblower lawsuit alleges the false charges totaled “hundreds of millions of dollars.”

Many of the Sutter hospitals named in the Department of Justice settlement with CHW and Sutter were also named in the 2009 whistleblower lawsuit, which is still making its way through the courts.