The investigation into a key interest rate manipulation scandal has taken a possible criminal turn with British authorities announcing the arrest of three men.

The UK’s Serious FraudOffice (SFO) Tuesday announced that, with the assistance of the City of London Police, it executed search warrants at three residences, and that three men have been arrested and taken to a London police station for questioning in connection with the investigation into the manipulation of the London interbank offered rate (LIBOR).

At this point, no charges have been announced. The SFO says the three men, aged 33, 41, and 47, are all British nationals currently living in the UK.

The SFO, which is responsible for investigating and prosecuting serious and complex fraud and corruption, announced back in July that it would investigate the LIBOR rigging scandal.

While a parliamentary review of the issue recommended widening the definition of the criminal offence for market abuse to include the manipulation of LIBOR and other benchmark rates, David Green, director of the SFO, has said that he is satisfied that existing criminal offences “are capable of covering conduct in relation to the alleged manipulation of LIBOR and related interest rates.”