A DETECTIVE investigating Consumer Council complaints against a Mongkok sex shop was threatened with assault when he failed to buy anything. At least two men in the Soy Street shop threatened to beat up the anti-triad squad officer if he did not buy coupons worth $800, which could then be used to purchase pornographic films or sexual aids. Detectives waiting outside the shop burst in and arrested the four men on the premises when the argument erupted. Police seized eight pornographic master tapes, two pornographic discs and 34 battery-operated sex gadgets. Detective Senior Inspector Chow Chong-wai said at least two men who had been cheated by the shop had been too embarrassed to tell the police, but had made official reports to the Consumer Council who contacted the police.