AN INMATE was battered to death in a riot at the controversial Shek Kwu Chau drug rehabilitation centre yesterday. More than 40 Marine Police were called to the island after about 30 drug addicts fought a pitched battle using chairs, planks of wood, metal bars and broom handles in the early hours of yesterday. The riot was sparked when a supervisor refused two inmates bottles of beer. The two men left their dormitory in search of beer about 1 am. An argument flared when the supervisor refused their request. The pair returned to the dormitory and a short while later the riot started. It is believed the other inmates were upset the men had been unable to get any alcohol. After more than 40 police and staff brought the incident under control they found the blood-spattered body of 49-year-old lorry driver Lo Kwong-chi. He had severe head and body injuries. Lo was rushed to the St John Hospital on Cheung Chau and certified dead on arrival at 3 am. The victim was in his second week of treatment for heroin abuse and is known to have been to the centre on several previous occasions. Another man was taken to the Cheung Chau clinic with hand wounds but was later discharged. A total of 45 Regional Crime Unit and Marine Regional Intelligence Unit officers were still at the scene last night interviewing more than 60 witnesses. Five men aged between 24 and 48 were arrested early yesterday and another four men were arrested inside the rehabilitation centre last night. At least one of the men is likely to face murder charges. All nine men were transferred from the Shek Kwu Chau last night to Marine Police headquarters in Tsim Sha Tsui where they were being held for questioning. During a search yesterday police found 70 weapons from an area outside a dormitory block, which was sealed off after the incident. When the Sunday Morning Post visited the centre on the island off Lantau last night, the scene was calm. All the addicts enter the centre voluntarily. It is funded by the Government and run by the Society for the Aid and Rehabilitation of Drug Abusers (SARDA). The programme has been called a ''failure'' and a ''waste of public money'' by the Director of Audits because of the scheme's high drop-out rate. In 1989 and 1990, only 6.5 per cent of the patients stayed for the full four to six months. Some inmates have given up on the scheme after complaining so much heroin was available on the island it was impossible to kick the habit. The ages of those who took part in the riot were between 19 and 45, and all had been admitted in the past two or three weeks. Speaking on the island, Chief Inspector Anthony Madin said: ''They are all on medication and going through withdrawal, that may have been a factor. ''People were just grabbing anything that was lying around to fight with. It could have been very serious but they quickly came to their senses. ''There is no tension there now, everything has settled down. We will not be keeping a presence here tonight.'' The victim lived in Fai House, one of three dormitories for new inmates. Each holds 60 men. Each patient on the island spends three weeks on medication - usually methadone - before starting rehabilitation. A member of staff claimed the dormitories, set up in July last year, were overcrowded. ''The fight broke out after the man who was killed failed to get beer for other inmates. I don't know why he was told to get beer,'' he said. ''Minor quarrels happen among inmates from time to time, but serious fights like this one in which a person gets killed has not happened before.'' The centre's acting superintendent, Peter Wu, declined to comment on the incident.