Hong Kong police have broken up a crack cocaine factory at a luxury flat in Yuen Long, seizing the largest haul of raw drug materials in 10 years and arresting four men, one of them Peruvian. The ingredients – thought to have been flown into the city from Peru – could have made batches of the drug worth HK$59 million, officers said on Sunday. The police operation, in Hung Shui Kiu on Friday, led to the seizure of 10kg of suspected crack cocaine and 150kg of materials to make the drug. The raw materials could have made another 50kg of drugs, the police said. Four men aged between 19 and 38 were arrested. They included a Peruvian national who arrived in Hong Kong two weeks ago on a tourist visa, and is suspected to be the group leader. Officers said he was sent to the city to be the chemist for the operation. Student arrested in connection with HK$11.7 million phone scam The suspects were charged with manufacturing dangerous drugs and will appear at Tuen Mun Court on Monday. The maximum penalty for drug manufacturing is life imprisonment. The syndicate rented a 1,000 sq ft luxury flat one month ago and tried to cover the smells emanating from their factory with fragrant oils. According to police, drug cartels in Peru sent the raw materials by air cargo in 10 boxes. Customs officers did not detect the material because it was mixed with “acidic-smelling powders”. Police said they believed it was the first time a luxury flat had been used as a base for making drugs. “One of the reasons the syndicate chose to rent rather luxurious premises was that it provided a front to make it less suspicious and more difficult for us to detect [the factory],” Chief Superintendent Ma Ping-yiu, of the Narcotics Bureau, said. Police also seized drug-making materials such as small stoves, flammable chemicals and other tools. Police figures showed cocaine seizures in the city rose about 97 per cent last year to 576kg, compared with 292kg in 2015. Last week, more than 3 tonnes of stimulant khat were seized by police and customs in several operations this year – more than three times the amount seized in all of 2016. In May, police made their biggest seizure of cannabis plants since 1990, after raiding two factory units in Tuen Mun and Yau Tong which were used to grow the plants. Despite the record hauls, police continued to insist there was no evidence Hong Kong had become a transit point for drugs.