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Man set up devices in Singapore blasting 50,000 scam calls in 50 minutes; victims lost S$1.6 million
The syndicated operation involved masterminds believed to be Taiwanese, drawing from a SIM pool purportedly located in Malaysia that housed multiple SIM cards in a single system.
The devices and a CCTV camera in one of the raided bedrooms. (Photo: Court documents)
Lydia Lam
02 Apr 2026 12:05PM (Updated: 02 Apr 2026 02:03PM)
SINGAPORE: A Malaysian electrician was recruited by a syndicate and travelled to Singapore to set up devices in a rented house that would blast thousands of automated scam calls, with call origins masked to appear like they were being made locally.
The devices transmitted over 50,000 call sessions over a 50-minute period, linked to around 18,000 phone numbers, 40 of which later featured in 42 police reports.
The call sessions contained automated voice messages perpetuating scams from purported government agencies or financial institutions.
In under three weeks, victims of these scam calls suffered losses of more than S$1.6 million (US$1.2 million).
Chong Wei Hao, 42, was sentenced to jail for five years and three months and fined S$895 on Thursday (Apr 2).
He pleaded guilty to one count of being party to a criminal conspiracy to deceive Singapore residents into believing the false information presented to them through the use of the telecommunication devices he had installed and maintained.
THE CASE
Chong was a freelance electrician with about 15 years of experience in the trade in November 2024 when he was looking for jobs on Telegram for extra income.He came across a post advertising a job vacancy for an electrician, with a monthly salary of 3,000 ringgit (S$956).
Chong then chatted with a Telegram user named "NASA", who told him that he would be given an advance payment of about USDT 700, a cryptocurrency pegged to the US dollar.
In exchange, he would have to rent an apartment in Singapore among other tasks.
Chong agreed to the job.
He carried out various tasks following instructions by "NASA". He went to Singapore for day trips in March 2025 to look for a rental apartment.
He rented a unit in Chai Chee, asking the landlord to equip it with high-speed broadband. He also asked for the room locks to be changed and said the bedroom should not face any neighbouring unit.
Chong emphasised the need for high-speed broadband with at least 1 gigabit per second.
He lied that he was the manager of a dim sum shop and that the unit was to house female employees.
He gave the identification of a Malaysian woman provided by "NASA" to convince the landlord about the tenancy.
Chong signed a tenancy agreement to rent the unit for six months for S$18,000. He also spent 3,000 ringgit to buy daily amenities and a new lock for the main gate, using cash he received in person in Malaysia.
THE INSTALLATION
In late March 2025, "NASA" instructed Chong to bring telecommunication devices into Singapore and install them there.These devices, known as Voice over Internet Protocol Global System for Mobile communications Gateway devices, or VoIP GSM Gateway devices, provide live broadcasts of the telephone signal from the IP network to the cellular network.
Chong received USDT 700 as advance payment around that time and made four trips into Singapore from Malaysia to install the units.
He installed a total of nine out of 20 planned devices in two bedrooms in the Chai Chee apartment, using his experience and technical knowledge.
Chong maintained the devices by testing broadband connectivity and bringing in racks to place them on an elevated platform for a stronger signal.
He installed two closed-circuit television cameras to monitor the bedroom entrances and avoided driving his own car into Singapore to minimise the chances of being searched and discovered.
THE SYNDICATE'S OPERATIONS
The court heard that the devices were to be used as part of a syndicated operation.The masterminds would initiate a call from outside Singapore, pre-configured to play automatic scam voice messages when answered.
The call would be directed to a centralised system known as a SIM pool, which houses multiple SIM cards in a single system.
The SIM pool, which was located outside Singapore, would select an appropriate SIM card based on predefined criteria such as cost, location, network and quality.
The call would connect to the devices, placing it on a cellular network in Singapore. Because the devices were located in Singapore, the call would appear local to the intended recipient.
As the devices installed by Chong concealed the true origin of the call, the masterminds of the syndicate could make remote calls without physically being present.
The operation was more resistant against network issues or blocking attempts because different cellular networks could be tapped on.
A single mastermind could potentially manage a large number of outgoing lines through multiple SIM pools, said the prosecutor.
Masterminds could also optimise costs by choosing the cheapest route for each call.
Before Chong installed the devices in Singapore, he carried out similar installations in three apartments in Johor Bahru, Malaysia, in early 2025.
He also received Singapore-registered SIM cards and delivered them to unidentified people in Malaysia.
At the time, Chong knew about the syndicated operation and possessed the technical knowledge and awareness that the devices were intended to broadcast scam voice messages and advertisements of illegal activities like online gambling.
He knew these were illegal in Singapore, and that the SIM pool was possibly located in Malaysia, with the masterminds possibly Taiwanese running the operation in Taiwan.
Chong had taken part in the operation solely for financial gain, court papers stated.
LOSSES
Between Apr 4, 2025 and Apr 16, 2025, the devices transmitted call sessions targeting victims in Singapore.A total of 131 unique phone numbers were traced to the Chai Chee unit as a potential scam call blasting activity site.
These 131 numbers later featured in 75 different police reports relating to scams.
In three of the reports, victims suffered losses amounting to S$1.6 million in fake Monetary Authority of Singapore investigator scams. The amount has not been recovered.
On Apr 17, 2025, police officers from the Commercial Affairs Department raided the unit, engaging a locksmith to get past the padlocked gate.
The police found the nine devices, CCTV cameras, a modem and a router in the unit.
The forensic team found that the devices had transmitted over 50,000 call sessions in total over a 50-minute period.
These were linked to around 18,000 mobile numbers, 40 of which featured in 42 police reports.
Of these police reports, 13 were for impersonation scams involving government officials. One of them was lodged by a 79-year-old retiree who lost S$6,300.
A day after the police raid, "NASA" asked Chong to check the devices in the unit as malfunctions had been detected.
Chong went to Singapore and realised he could not enter. When he peeked inside, he saw that the devices had been removed.
He updated "NASA" and left on his instruction.
Chong was arrested in Johor Bahru on Jun 28, 2025, and handed over to the Singapore police two days later.
SENTENCING ARGUMENTS
The prosecution sought between five-and-a-half and six years' jail and a fine to disgorge the profit made by Chong.Chong was defended by Mr Cory Wong from Invictus Law, who sought not more than four years' jail.
Mr Wong said his client had no control over what the other people "downstream" did.
"He didn't push the lambs to the slaughter," said the lawyer. "He may have set up the pen, but is he as culpable as the butcher? We are saying he is not."
He said Chong has a Thai wife and two children back home. His wife holds a long-term pass in Malaysia and works as an online fashion retailer, but this is not enough to support the family, which includes Chong's elderly father.
As Chong's wife depends on him to have her long-term pass renewed annually, there is a risk that her pass will lapse in Chong's absence.
District Judge Eddy Tham said the harm in this case was "clearly high", with victims suffering S$1.6 million.
The operation had a "staggering" reach and it was also sophisticated and elaborate, allowing the masterminds the safety of being out of jurisdiction, said Judge Tham.
For being party to a criminal conspiracy to commit cheating, Chong could have been jailed for up to 10 years and fined.
