WHEN the Carrian empire collapsed in October 1983, rumours about the group's financial troubles had already been circulating for months. But when it finally went under with debts of more than US$1 billion (HK$7.7 billion), the shock was still unbearable for many investors who witnessed the evaporation of their investments in the listed company. The timing of Carrian's downfall aggravated the jittery mood of the community, which was affected at the time by a crisis of confidence caused by a stalemate in Sino-British negotiations on the future of Hong Kong. The local currency went into a free fall, which had to be arrested by pegging it to the US dollar. Seventeen years on, the peg remains, for understandable reasons. But no one expected the Carrian saga to drag on for so long. Indeed, but for the dogged persistence of the Independent Commission Against Corruption, the Carrian investigation could have come to an early end. This would have been wrong, for no criminals should be allowed to remain at large, especially after they have fraudulently fattened their pockets. The formula that George Tan Soon-gin used to build up Carrian was crude. He started by buying some small properties, which he then used as collateral to raise money from banks to buy bigger ones. By repeating the process over and over again, he amassed assets worth many times the value of the first pieces of property he purchased, and created an image that his funds were limitless. When bankers asked where his money came from, he reportedly told them that times were difficult for Malaysian Chinese; then he would wink. Some bankers might have been very gullible, and they paid for their stupidity. But as the trials of Ewan Launder and other key culprits revealed, what sustained the money flow to Tan and his bogus businesses were bribes he paid to bank officials. The Carrian case is a costly lesson to financial institutions, but what it teaches is something very basic - a need to stick to due diligence tests and not to be swayed by dubious credit reports by zealous staff. Unfortunately, it is also a lesson that is easy to forget, evident in a recent spate of graft-facilitated frauds involving the issuing of letters of credit. Unless, and until, greed ceases to be part of human nature - which is an unlikely development - corruption must remain a high risk crime.