HONG KONG (AP) — Hong Kong police said Thursday that they seized 195 million Hong Kong dollars ($25 million) worth of illegal drugs as part of a monthslong investigation, the largest seizure of the year.

Police said the drugs, including 148 kilograms (326 pounds) of crystal methamphetamine and 86 kilograms (189 pounds) of heroin, were uncovered Wednesday in an industrial building. A suspect was arrested and was due to appear in court Friday.

Police said at a news conference that the drugs were linked to a syndicate that had been under investigation for months. In May and July the investigation led to the arrests of eight men and four women aged between 16 and 45 on suspicion of manufacturing and trafficking drugs as well as obstructing the police.

“According to our previous experience, most of the heroin come from the Golden Triangle, or the Golden Crescent … which includes Thailand, Laos or Burma,” said Chan Kong-ming, superintendent of the Narcotics Bureau. Burma is the previous name of Myanmar.