Fiolic will be questioned on Saturday by the anti-corruption office USKOK and the Zagreb County Court, which will decide whether to put him in custody.
Fiolic was arrested in Velika Mlaka after investigators searched his house and offices.
Madunic assumes that Fiolic was arrested over the sale of a building to Hypo Leasing and then to the government in which the state was defrauded of at least HRK 30 million.
According to the media, Fiolic sold the building to Hypo Leasing and in April 2009, the regional development ministry took out a 10-year lease on it at double the sale price. Fiolic, who owns a chain of butcher shops, was questioned about this case in March for the second time.
(EUR 1 = HRK 7.5)