A woman says she was fired from her job at a Casper hospital because she told federal authorities about possible billing fraud there.

Gale Bryden made the accusation against Wyoming Medical Center in a lawsuit unsealed this week.

The hospital released a statement  denying the allegations.

The Associated Press reports,  Bryden was responsible for collecting fees at the hospital that had been denied by insurers. She first filed a lawsuit on behalf of the federal government in October 2007. That suit, unsealed in the fall, alleged that the hospital altered records to collect higher fees from Medicare and Medicaid programs by changing the admission status of patient. An amended lawsuit filed in 2009 and unsealed this week accuses the hospital of billing for canceled surgical procedures.