Nineteen people were arrested, among them a woman, making this the largest catch in an operation this year.

More than $35,000 was seized, along with computers, cellphones, data storage devices and ATM cards.

Investigations are ongoing, but police believe the syndicate to be behind at least 500 harassment cases related to loan-sharking.

Among those nabbed in the eight-hour-long operation in Pandan Gardens, Jurong, Bishan, Tampines and Henderson were the syndicate's 31-year-old leader and his four deputies.

The rest were the runners, who meet debtors to hand over the loans, to collect repayments, to give them the account numbers into which money is to be transferred or to harass them into coughing up the repayments.

Police said the lone woman arrested was helping her boyfriend, a runner.

Loan records stored in the seized computers indicated that at least 5,000 people have borrowed sums of between $500 and thousands of dollars.

These numbers suggest that it is 'quite a big syndicate' even though it does not operate in fixed locations here, said the director of the Criminal Investigation Department, Senior Assistant Commissioner (SAC) Ng Boon Gay.

He noted that the ring made use of technology, conducting a lot of its transactions over the Internet or via funds transfer.

Read the full story in Tuesday's edition of The Straits Times.