PITTSBURGH — The University of Pittsburgh Medical Center say identity thieves have used the personal information of 22 employees to file bogus federal tax returns.

The hospital network is working with the Internal Revenue Service and other federal investigators to determine the scam’s scope.

It’s not clear whether only UPMC employees were being targeted. UPMC spokesman Gloria Kreps says such frauds are very common during tax season and UPMC believes its workers were targeted as part of a “broader fraud.”

The IRS says 1.2 million taxpayers were the victims of similar fraud in the 2012 fiscal year. The agency intercepted about 5 million bogus returns for the 2012 tax year.

The U.S. attorney’s office in Pittsburgh confirmed that federal authorities are investigating.