The investigation, which began in 2008, is being led by the special tax-inspection agency, the BBI. The complaint targets two parts of the Santens family, as well as business partner Lucien Vanwynsberghe, and alleges the family used its own international subsidiary, Santens International, as well as straw-man shell companies in tax havens, to launder income and avoid paying tax.

Santens, based in Oudenaarde, was set up in 1913 and now holds a leading position in the production of bath and kitchen linens, manufacturing 100,000 towels a day, 90% for export.

The senior suspect in the case is Marc Santens, now 83 years old, former chairman of Kredietbank, now KBC, and ennobled as a baron by King Boudewijn in 1986. The second generation of Santens in the business, he has a long and distinguished history in Belgian business, having been a director of Sabena, Alcatel-Lucent Bell and Corelio Publishing.

Also a suspect is his nephew Lieven Santens, 76, a former mayor of Oudenaarde; his son Jean-Baptiste, now managing director of the company; and Vanwynsberghe, with whom the Santens family own McThree Industries, a carpet manufacturer based in Waregem, West Flanders.