TAIYUAN, May 20 -- A total of 257 kilograms of drugs and four suspects have been seized during raids in north China's Shanxi Province, local police said Saturday.

Police were tipped off in March that the suspect surnamed Su could be involved in drug trafficking in Linfen City.

In April, about 77 kilograms of drugs were seized during a raid on Su's home. Another 180 kilograms were captured in May in a drug den in Yuncheng city.

Four suspects involved were in police custody. The investigation is underway.