An investigation is being carried out into the Scottish banking sector.
On Tuesday, the Crown Office said "an investigation has been under way for some time" and the scope of the inquiry would be extended "as a result of recent developments".
They said the Serious and Organised Crime Division is leading the investigation.
It comes after Barclays chief executive Bob Diamond resigned in the wake of the rate-rigging scandal.
The bank was fined £290m by UK and US regulators for manipulating the Libor, the rate at which banks lend to each other.
Royal Bank of Scotland has also confirmed it is being investigated for allegedly manipulating the Libor.
Four traders at the bank have been sacked since October 2011 over the scandal.