DSI officials, armed with search warrants issued by the Criminal Court, on Thursday conducted searches at six locations in Bangkok, including showrooms of Maserati, Rolls-Royce and Aston Martin at the Siam Paragon shopping mall.

Four cars were confiscated at the Maserati showroom, and two each at the Rolls-Royce and Aston Martin showrooms.

Searches were also conducted at the offices of Perma Motor Co Ltd in Lak Si district and Master Group Corporation (Asia) Co Ltd in Wang Thong Lang district. DSI officials found a number of car import papers at the two locations, and the documents were confiscated as part of an ongoing investigation.

Another DSI team also searched Millennium Auto building in Bang Kho Laem district and a nearby showroom of Rolls-Royce Motor Cars Bangkok, where 30 vehicles were confiscated.

In addition to Maserati, Rolls-Royce and Aston Martin, McLaren and Ferrari cars were also confiscated during the DSI searches on Thursday.

The DSI investigators are looking into the seized import documents in an attempt to determine whether importers quoted unusually low vehicle prices in order to avoid the high customs duty of 300 per cent.

The operation on Thursday came after earlier searches at nine locations on May 18 when 122 luxury vehicles were confiscated from Niche Car Group showrooms as part of an investigation into alleged import-tax evasion.

Authorities said the vehicle importers allegedly quoted prices no more than 40 per cent of the actual prices and managed to save between Bt10 million and Bt18 million in import duty for each of the 122 imported vehicles. In total, that cost the government Bt2.4 billion in lost revenue.