SINGAPORE - A suspected drug syndicate leader was arrested following an operation mounted by the Central Narcotics Bureau (CNB) on Tuesday evening.

Three other suspected drug offenders were also arrested and more than $103,000 worth of drugs were seized, including about 400g of Ice and ketamine, more than 900g of heroin, more than 800 Erimin-5 tablets and 90 Ecstasy tablets.

A small amount of cannabis and opium, three digital weighing scales and improvised drug-smoking apparatus were also recovered.

On Tuesday evening, CNB officers observed a rider of a Malaysia-registered motorcyle entering a unit along Hamilton Road and leaving 15 minutes later.

Officers tailed the 43-year-old Malaysian and intercepted his motorcycle at the junction of Jalan Besar and Lavender Street. They recovered Erimin-5 tablets and $6,000 cash after conducting a search of his bag.

Meanwhile, another group of CNB officers raided the Hamilton Road unit, where they arrested a 55-year-old Singaporean man, believed to be the drug syndicate leader.

The same evening, officers nabbed a 37-year-old Singaporean man, suspected of being associate of the drug syndicate leader, and a 55-year-old Singaporean man suspected of being drug abuser.

Investigations into the drug activities of the four suspects are ongoing.

Under the Misuse of Drugs Act, those found guilty of trafficking more than 15g of diamorphine (or pure heroin) face the death penalty. The amount is equivalent to 1,250 straws, enough to feed the addiction of about 180 abusers for a week.