JEREZ (Agencies) A major investigation is ongoing that apparently involves a company called BullForex, which offered gains of up to 500% 'in less than a year', according to its advertising. The company was supposedly involved in the international currency exchange business. Over 200 'investors', mostly from Jerez, are affected, having given up to €3,000 to the company to invest on their behalf and the fraud amounts to over one million euros so far. (The tax authorities do not investigate transactions below that amount.) The fraud unit of the National Police has been looking into the matter since March last year and the head of the business was first arresteda little later. However, the number of people denouncing the fraud has grown exponentially since the first ten or so 'victims' reported it. Investigations are being hampered by the fact that many of the 'victims' gave only their first surnames and rarely their addresses.