Two men have been arrested by detectives investigating a suspected fund management fraud worth more than £50 million.
City of London Police held the men during three dawn raids at addresses in London and Surrey.
The investigation is linked to three UK-based financial consultancies whose operations were frozen by the Financial Services Authority (FSA) in 2008.
Business Consulting International (BCI), John Anderson Consulting and Kenneth Peacock Consulting are under police investigation.
Some of those involved in the companies are suspected of mishandling millions of pounds of investor funds.
A 40-year-old man was arrested on suspicion of conspiracy to defraud, money laundering and fraud by misrepresentation. He has been released on police bail.
A 43-year-old man arrested for the same offences remains in custody. A third suspect will be arrested by appointment later this week.
The FSA has also issued proceedings against three individuals linked to the consultancies for allegedly taking unlawful deposits and running an unauthorised collective investment scheme.
Detective Inspector David Manley, of City of London Police, said: "We are working in partnership with the FSA to tackle this complex investment fraud that involves hundreds of victims and losses suspected to run into tens of millions of pounds.
"It is vitally important for people who have been involved with, or suspect they could be a victim of BCI, John Anderson Consulting and Kenneth Peacock Consulting to contact the City of London Police as soon as possible."
