The Causeway Bay jewellery company robbed yesterday of $250,000 of goods had left its double-glass security door open to attract more customers. Koo Tong-fat, administration manager of the Chow Tai Fook Jewellery, said yesterday it could have avoided being robbed if the security door had been shut. 'We have installed the double-glass, electronic security door for a long time. And we used to keep the door shut until recently amid the economic slump. It's getting more and more difficult to do business,' said Mr Koo. 'We want to attract more customers to come in. But this time we attracted the robbers. We never thought of this. 'We will keep our security door tightly closed in the future.' The shop reopened last night at 6 pm after police interviewed staff and took away bullets and cartridges - an unarmed security guard was opening and closing the door for each customer. 'They spoke Cantonese like Hong Kong people,' a senior staff member said. 'They just stormed in, shouted 'robbery!', fired and grabbed the goods.' Staff threw themselves on to the floor. The watches and necklaces taken were on the counter because they were being shown to a customer and were relatively low-value goods. The shop sells diamond rings worth in excess of $600,000 each. After grabbing the goods the robber fled. 'They were not in the shop even one minute,' said Bill Cheung Man-piu, superintendent (crime) for Hong Kong Island. He said police were investigating apparent similarities with a robbery at Dickson Watch and Jewellery Company in Windsor House, where goods worth $3 million were stolen. No one has been arrested for that crime.