Four doctors who worked at a former Tenet Healthcare Corp. hospital agreed to pay $27.1 million to settle a federal investigation into claims they performed unnecessary procedures at the company's Redding Medical Center in California.

Tenet also agreed to pay an additional $5.5 million to settle claims against the company, U.S. Attorney McGregor W. Scott in Sacramento said Tuesday. Dallas-based Tenet had agreed to pay $54 million in August 2003 to settle government civil claims in the case.

In 2003, Tenet established a $395 million fund for 750 people who filed civil lawsuits against the company claiming doctors had performed unnecessary heart surgeries at the Redding facilities. The company is awaiting a jury verdict in a separate case filed by federal prosecutors in San Diego over claims a Tenet hospital offered illegal kickbacks to doctors.

As part of the settlement, the government said it would not file criminal charges. McGregor said the government "felt criminal charges couldn't be sustained."

Tenet sold the Redding Medical Center to Hospital Partners of America Inc. in July 2004.

"Tenet and its subsidiaries have expressly denied that Redding Medical Center submitted false claims to government health care programs for cardiac procedures at Redding," Tenet said in a statement. The settlement ends a three-year criminal investigation without charges against individuals or the company, the statement said.