A number of former Lloyds Banking Group traders have been quizzed by the fraud squad as part of its ongoing investigation into Libor manipulation.
The Serious Fraud Office (SFO) has been probing the rigging of the benchmark rate since 2012.
Now, Bloomberg has reported the prosecutor has called in a number of ex-Lloyds traders in recent months to be questioned under caution about the scandal.
Interviews are usually carried out under caution when somebody is considered a possible suspect, and the answers given can be used in court if needs be.
A Lloyds spokesperson said: "We are unable to comment on speculation regarding possible ongoing investigations."
The SFO declined to comment.
Lloyds itself was handed hefty fines back in 2014 for failings over rate rigging, including a £105m fine from the Financial Conduct Authority (FCA) – the joint third-highest fine at the time to be handed down by the regulator and the seventh linked to Libor – and $86m (£69.8m) from the US Department of Justice.
At the time, the FCA said 16 people at Lloyds, including seven managers, were involved in, or at least aware of, some sort of Libor manipulation.