Did that happen after the LIBOR scandal?
https://wallstreetonparade.com/2012/12/why-was-libor-rate-ri...
> What the complaint makes clear is that it should not have taken five years to bring these charges. The traders effectively handed the Justice Department a slam dunk case by documenting each maneuver to rig the international interest rate benchmark known as Libor via instant messages recorded on a Bloomberg computer terminal.