THE police opened their own Mongkok fashion boutique to flush out local blackmailers, the District Court heard yesterday. Two officers disguised as shopkeepers spent more than three months selling women's clothing, prosecutor Newman Wong said. Their efforts were rewarded when four men showed up demanding protection money. On December 18, 1993, they made their first call while the store was still being decorated. Sit Chi-kwan and Lai Kwok-ping and two other men barged through the door, the court was told. One of them announced that he was a member of the 14K triad society and demanded to see the shop's owner. The two officers told their callers that the proprietor was not in the building. The four men left, but warned they would be back. Two days later, Sit, Lai and another man entered the shop again and demanded that $2,000 protection money be paid to them each month. They returned several times to repeat their demands, warning the officers that there would be trouble if the money was not paid. On February 2 last year, Lam Cho-yin entered the shop and suggested the officers pay lai see over the Lunar New Year. Their $3,000 to $5,000 would make up for the missing monthly payments, he said. Three days later, the officers handed Sit a packet containing $100. When he discovered how little money was inside the envelope, Sit hurled it away and stormed out of the shop, the court heard. On March 30, one of the shopkeeping officers asked Lai for a loan. He agreed to lend her $1,000, provided she pay 20 per cent interest every 10 days. Sit, 28, pleaded guilty to blackmail and was sentenced to a year in prison. Lam, 33, admitted criminal intimidation and was given a two-year suspended sentence. Lai, 37, pleaded guilty to blackmail, carrying on the business of a money lender without a licence and lending money at an excessive interest rate. Judge Whaley sentenced Lai to 15 months which he added to the prison term Lai is currently serving for another crime.