A trader who worked for UBS and Citigroup, along with two inter-dealer brokers were questioned by police in London on Tuesday after being targeted in the first arrests in the widening global probe into the manipulation of Libor.

The arrests mark a public shift of direction in the investigation into the potential abuse of the benchmark interest rate, which has embroiled at least 20 of the world’s biggest banks and inter-dealer brokers.

Tom Hayes, a 33-year-old former trader who specialised in products pegged to yen-denominated Libor, and whose employment has stretched from Tokyo to London, was arrested and questioned at a London police station on Tuesday after his home was searched by City of London Police and the Serious Fraud Office, people familiar with the investigation told the Financial Times.