The Serious Fraud Office is conducting an investigation into the collapsed car firm Ken Thorne World of Cars.
Ken Thorne's car group used to sponsor Cardiff City FC
One person has been arrested and officers from South Wales Police carried out three searches at addresses in the Cardiff and Barry area on Wednesday morning.
Two of these addresses, were residential and one was a business, police said in a statement.
Police vehicles were seen at former company owner Ken Thorne's house in Groesfaen, between Cardiff and Llantrisant.
The car sales chain, which had garages across south Wales, shut suddenly in 2002, owing millions to creditors.
After the company closed in September 2002, liquidators revealed the company had a deficit of £5.5m.
Customers and creditors owed money by the firm were told they would probably not get it back.
A police vehicle at Ken Thorne's house at Groesfaen
Up to 240 staff at the chain lost their jobs, with many still owed wages when the group suddenly stopped trading.
Before the dealerships shut down, the group had a six-figure sponsorship deal with Cardiff City Football Club.
Cardiff-born businessman Mr Thorne had made his car company into one of the region's most successful brands before its unexpected closure.
The former world powerboat champion employed his two sons, Nigel and Chris Thorne, at the business.