AN unemployed man who blackmailed a supermarket so as to pay off debts to loansharks was yesterday jailed for three years by the High Court. Li Man-keung, 32, tried to extort $150,000 from the Wellcome chain, claiming he had laced cartons of drink at some of its stores. Li admitted blackmail before a magistrate and was committed to the High Court for sentencing. Acting Senior Crown Prosecutor Paul Madigan told Deputy Judge Wong that an assistant manager of Wellcome supermarket at Chi Kiang Street, Kowloon, received two phone calls from Li on March 24. He claimed drinks on sale in the shop were laced with a substance that caused stomach pains, and demanded $150,000. He called again the next morning and told the manager that he had laced the drinks on sale at four branches of the supermarket. In a later call, he said he had laced the drinks at only two shops. The manager persuaded him to cut his demand to $100,000. Five of the calls were traced by police to an acupuncturist's clinic next to some residential units where Li was a tenant. Police mounted a surveillance operation and Li was arrested while he was still on the phone with the supermarket manager. Investigations showed that no drinks were laced and police found no noxious substances at Li's home. His counsel, John Marray, said in mitigation that it was an amateurish attempt. Li was more of a nuisance than an evil person as he had no intention of putting anything in the drinks. Mr Marray said Li borrowed money from loansharks to save his business. When he was unable to repay the $75,000 debt, the loansharks threatened him and damaged his home. One of them told him that, if he could not get money by legal means, he would have to find some illegal way to repay the debt. He hatched the idea of blackmail while walking past a supermarket, said counsel.