They are looking into Germany's winning bid to host the 2006 World Cup
German football legend Franz Beckenbauer is among four people being investigated by Swiss prosecutors for involvement in an alleged corruption scandal.
They have confirmed they are looking into Germany's winning bid to host the 2006 World Cup, which Beckenbauer headed up.
The World Cup winning captain and coach has always denied wrongdoing.
FIFA is also investigating the matter.
Beckenbauer captained Germany to World Cup and European Championship glory in 1974 and 1972, as well as enjoying club success with Bayern Munich.