It took a gang of nine robbers months to plan the heist they pulled off in front of their victim's two-year-old son.
The Nov 5, 2014, robbery of a money changer in Aljunied Crescent involved more than $600,000 in cash and was "meticulously planned", said District Judge Lim Keng Yeow yesterday.
He added: "The amount was very substantial... violence was used, with threats on the boy."
Three members of the Malaysian group were sentenced to jail and caning yesterday after pleading guilty to gang robbery last month.
Saravanak Kumar Karunanithy, 30, and Vekneswaran Sekaran, 31, were each jailed for seven years, while Selvam Karupaya, 33, was jailed for five years and nine months. Each man will also receive 12 strokes of the cane.
Three of their accomplices, Ravi Sandhira Sagaran and Tachana Moorthy Peromal, both 30, and Annadurai Raman, 44, were dealt with in the Singapore courts early last year.
Another three Malaysians, Sivaraam Monion, 29, Baskaran Balakrishnan, 34, and David Mark Mari, 35, are still at large.
In April 2014, Tachana and Baskaran were part of a group that hatched a plan to rob money-changing business manager Ali Yousof Saiboo, then 35, in Singapore.
In September and October that year, Vekneswaran, Saravanak and Selvam entered Singapore multiple times to meet their accomplices and plan the robbery.
The group decided to rob Mr Saiboo in early November that year.
Vekneswaran, Saravanak and three of their accomplices took a car together shortly before midnight on Nov 4, 2014.
Three others monitored Mr Saiboo's movement.
Mr Saiboo left his home with his two-year-old son at around midnight. He drove to Changi Airport to meet his couriers and collected from them cash totalling $624,036.41 in different currencies.
The robbers sprang into action when they spotted Mr Saiboo in his car at an open-air carpark near his father-in-law's Aljunied Crescent home at around 12.50am.
They used their car to block Mr Saiboo's vehicle.
Deputy Public Prosecutor Michelle Lu said: "Upon realising that the door was locked, Saravanak proceeded to use a crowbar to forcefully hit the driver side window multiple times, causing the window to shatter.
"One of the robbers also threatened the victim in Tamil, 'You want me to kill your son?'"
Mr Saiboo was dragged out and assaulted.
The robbers then took the money, which was kept in a luggage bag, before fleeing the scene.
Selvam was not at the scene of the robbery, but the money was later placed in his car and he drove across the Causeway.
The other men also left Singapore within minutes of one another.
DPP Lu said US$30,000 (S$40,700) and RM23,645 (S$7,500) were recovered from Tachana during his arrest in Malaysia. The remaining amount has not been recovered.