When Mr Li Shu heard that an elderly customer wanted to remit $180,000 to China to buy Chinese herbs, the teller at a remittance company became suspicious.
"She was nervous and refused to say anything more than the reason for remitting the money," said the 36-year-old, who works at Hanshan Money Express Remittance.
"A lady claiming to be her younger sister was the one anxiously asking me how fast the money could be remitted and was constantly on the phone."
He did not know then that the 80-year-old customer had been contacted seven days earlier by someone impersonating a police officer from China, who claimed the old woman had sent an illegal parcel there and threatened to jail her if she did not remit the money.
The customer had to call the scammers four times a day each day. On June 24, she met a 65-year- old woman purportedly working with the "Chinese authorities". The woman escorted her to withdraw money from the bank, then headed to the remittance company.
Having encountered similar phone scams involving their customers before, Mr Li and his colleague, Ms Han Guiyuan, 46, decided to delay remitting the money and instead informed their managing director, Ms Thng Koon Eng, 61.
By then, the women had left. When they called the customer, her phone was answered by her "sister", who threatened to use another remittance company's services. Ms Thng spoke to the customer, who insisted she knew what she was doing.
The employees then called the police, who arrived within the hour. However, the customer had switched off her mobile phone and could not be reached.
The next morning, her brother saw the text message sent by the police and contacted them. All $180,000 was recovered that very day.
The female suspect is assisting the police with investigations.
For their timely intervention, the trio were given Public Spiritedness Awards by the Singapore Police Force yesterday.
"This case illustrates that strong police-community partnership helps to prevent, deter and detect crime. The police will continue to work closely with various stakeholders to prevent similar scam-related cases," said Deputy Assistant Commissioner of Police Arthur Law.
It is crucial to contact the police before the money has been remitted and withdrawn from the bank by the scammers, as it would be very difficult to recover the money after that, he stressed.
He said the police intend to work closely with remittance companies and banks to prevent similar scams from happening.
Many phone scam victims are elderly people, and the police advised the public to ignore unsolicited calls and callers' instructions to transfer money.
Anyone with information related to such crimes can call the police hotline on 1800-255-0000, or dial 999 for urgent police assistance.