The Federal Reserve Bank of New York will release on Friday documents showing it took "prompt action" four years ago to highlight problems with the benchmark interest rate known as Libor and to press for reform, an official said, according to Reuters.
I suspect we will see that the Fed was concerned with a climbing LIBOR rate. That markets rates were freezing up for LIBOR banks and rates were climbing for them during the financial crisis and that the Fed viewed this as a problem, since LIBOR was a benchmark for so many loans.
Thus, any manipulation was in the direction of a lower LIBOR rate, to lower costs for borrowers. A manipulation that was egged on by central bankers----and probably explians why the Fed was providing funds to European banks---to unfreeze the markets and push LIBOR down, since only central banks like the Fed and the Bank of England have the power of the printing presses to manipulate interest rates to any significant degree.