Washington - An unidentified employee of U.K. bank Barclays PLC told the New York Federal Reserve Bank more than four years ago that the bank was filing false reports on a key interest rate, according to documents released by the regional central bank Friday.

The documents show that a summary of this admission was quickly circulated throughout the U.S. government, including the Federal Reserve and the Treasury Department, in 2008. The Libor rate is at the center of a sweeping industrywide, cross-border investigation into the setting of interbank lending rates.

United Kingdom bank Barclays was fined $450 million for fixing Libor. Other banks across the world including Citigroup, JPMorgan Chase, the Royal Bank of Scotland and Deutsche Bank have said they also are being investigated.

Morgan Stanley analysts say the Libor scandal hits banks three ways - through fines, such as the one Barclays paid; litigation risk; and less certainty on future earnings as regulators and politicians demand Libor and broader industry structure change. In a note published Thursday, they said they expect fines equaling about 9 percent of 2012 earnings per share and litigation risk of roughly $400 million per bank.

Libor is based on rate submissions from a relatively small and select panel of major banks, including Barclays, and is calculated and published daily for several currencies by the British Bankers' Association.