Whistle-blowers tipped off the government to $1.3 billion worth of fraud cases over the last year, largely at hospitals or other health care providers, the Justice Department said Tuesday.

In all, the department recovered $3.1 billion in settlements — what prosecutors said was a record amount — from individuals and companies during the 2006 fiscal year that ended Sept. 30.

"Many of these cases were initiated by whistle-blowers," said Assistant Attorney General Peter D. Keisler, who oversees the department's civil division.

He called the $1.3 billion identified by whistle-blowers a recovery level "probably greater than most years, smaller than a couple." In return, whistle-blowers were paid $190 million over the year for alerting the government to the fraud.

The single largest settlement, worth $920 million, came against Dallas-based Tenet Healthcare Corp., the nation's second-largest hospital chain. Following claims from six whistle-blowers, prosecutors accused Tenet of overbilling the government for $806 million in Medicare payments, and paying $49 million in kickbacks to doctors who referred patients to the health care chain.