Three people are arrested for having $400,000 worth of the drug on their roof Customs officers yesterday raided a marijuana-growing operation being run on the roof of a Tai Po house. Thirty-eight plants worth an estimated $400,000 were seized. A woman, her husband and his brother were arrested. It was the third cannabis cultivation site raided by law enforcers in the past year. Police found 110 plants in a factory in Tuen Mun last July and three plants in Sai Kung in February. Head of the Customs and Excise Department's drug investigation group, Superintendent Cheung Chi-kwong, said officers mounted the raid after a tip-off and a week-long operation. Customs officers intercepted and searched one of the brothers near his home at Kam Shan village, Tai Po, at 12.40pm yesterday and found a small amount of marijuana. They then went to his three-storey house, where they found the plants, about a metre high, covered with tarpaulin sheets. A further 70 grams of cannabis and 1,000 seeds were seized in the house, where the two other suspects were arrested. Mr Cheung said it was believed the cannabis had been planted more than a month ago. The family was believed to have been carrying out a trial run and intended to increase the crop if it was successful. Mr Cheung said it would normally take two to three months before a cannabis plant was fully grown. The leaves of the 38 plants would have produced up to 3kg of dried cannabis which, at $150 a gram, would have been worth at least $400,000 on the street. 'It's believed a small quantity of the drug was for self-use while most of the stock was intended to be sold in the New Territories,' Mr Cheung said. He said they were still investigating where the suspects obtained the cannabis seeds. Mr Cheung said that while the weather in Hong Kong was not ideal for cultivating cannabis, the plant could still be grown given sufficient water, nutrients and sunshine. The three suspects are likely to be charged with cultivation of cannabis, an offence which carries a maximum penalty of 15 years' jail and a $100,000 fine. Mr Cheung said possession of cannabis seeds was also an offence, carrying a maximum penalty of life imprisonment and a fine of $5 million. The officer said most of the cannabis found in Hong Kong was smuggled from places including the mainland, Cambodia and Thailand.