SINGAPORE - Eight more suspects, including some who had earlier fled Singapore, have been charged over the $40 million SkillsFuture scam.

Some $20 million remains unaccounted for in the largest case of fraud perpetrated against a public institution in Singapore to date.

In an update of investigations into the scam, the High Court on Friday (Jan 11) heard the arguments an alleged mastermind made for bail.

Housewife Lee Lai Leng, 40, who was described by prosecutors as playing a "pre-eminent role" in the syndicate, had her fourth attempt to seek bail denied. Her first three applications were denied by the district court.

Lee and her husband Ng Cheng Kwee, 42, are said to be the key players among the five members of a syndicate who were charged in court in 2017 for various roles relating to the scam.

The number of people arrested and charged has since grown to 13, including some who had skipped town.

Between May and October 2017, the syndicate used nine shell companies - three training providers and six business entities - to submit more than 8,000 course fee subsidy claims to SkillsFuture Singapore (SSG).

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These were submitted on the basis that courses were provided by the three training providers to about 25,000 employees of the six business entities.

The fraudulent applications and claims were made via SSG's online portal, SkillsConnect, using the SingPass credentials of various people.

After $39.9 million was disbursed to the bank accounts of the nine companies, a network of runners was used to dissipate the criminal proceeds.

Lee's brother, Lee Chi Wai, 32, is serving a jail term of five years and eight months for helping her stash away $6.7 million in cash and 11kg of gold at his Sengkang flat.

Lee, who has been remanded in custody since November 2017, sought bail, contending that she needed to tend to her three children.

She also said she wanted to seek medical help for depression and argued that it was inconvenient for her to instruct her lawyers from prison.

Her lawyer, Mr Bachoo Mohan Singh, said her remand was "oppressive", given that other suspects, including some who had fled to China and withdrawn huge sums, have been granted bail.

Deputy Public Prosecutor Jordon Li said Lee should not be granted bail, given her "integral role" in the entire scam.

In the initial stages, she registered the business entities with SSG and allegedly submitted forged documents to support the bogus applications, said the DPP.

After the funds were disbursed, she allegedly received cash withdrawn by other syndicate members, hid the money at her brother's flat and used $626,500 to buy 11kg of gold.

The DPP said the Commercial Affairs Department (CAD) has seized and frozen assets of about $18.5 million.

This includes the $6.7 million, gold and about $11.1 million frozen in the bank accounts of companies and individuals that were used to receive criminal proceeds.

The DPP argued that there was a real risk that Lee could further dissipate the proceeds if she was granted bail.

Since her arrest, Lee has not given CAD any information to help in the recovery of funds and instead provided false information that hindered investigators, he said.

Lee was also at risk of absconding, he said, given that she faces a lengthy prison term.

Apart from 30 charges relating to the SkillsFuture fraud, she also faces four cheating charges for a separate scam.

The DPP added that after investigations into the SkillsFuture scam are concluded, additional charges may be tendered against Lee, which will increase the sentence that she may face eventually.