Cagliari, July 19 - Police arrested 16 people throughout Italy last month in a multi-million-euro fraud in which more than 100,000 tons of non-organic grain products allegedly were sold as organic, Sardinian authorities said on Friday. Investigators in operation "Bio Bluff" say they uncovered a massive, Sardinian-based scheme that obtained falsified certifications and false tax documents for organic suppliers, permitting the operators to sell products at the far higher price that organic products command. Probes into the Sardinian companies Kapo Terra Kommerciale S.r.l and Societa' Agricola Biostore S.s. revealed invoices covering more than 100,000 tons of grain products. Investigators also claim to have discovered tax evasion adding up to more than 55 million euros. The scheme had a pyramid structure, investigators say, with sham companies owned by a Sardinian parent company that were set up in the regions of Sardinia, Marche, Emilia-Romagna, Puglia and Veneto - ostensibly intermediaries for grain products made from organic cultivation.