NEA said this was likely caused by a hotspot and smoke plume detected in Johor, which is located close to Singapore.
The police said that the 34-year-old male driver of the car is assisting with the investigations.
Despite being given several warnings, he continued to disregard police instructions and was subsequently arrested for disorderly behaviour.
Preliminary investigations revealed that the rental car's key had been left unattended overnight on one of the vehicle's tyres.
MINDEF stressed that such false alarms divert security resources and can cause unnecessary public concern, and said investigations into the incident are continuing.
The offence carries a penalty of up to S$10,000 in fines, imprisonment of up to three years, or both.
The police said the man was arrested on suspicion of dangerous driving causing death, following investigations into the incident that occurred a day earlier.
The police noted a rising trend of Malaysians travelling to Singapore to assist scam syndicates in collecting cash, gold and valuables from victims.
Under Singapore law, those convicted of trafficking more than 500g of cannabis may face the death penalty.
The bus operator said the bus captain made an incorrect turn into Loyang Rise and grazed several vehicles parked along the roadside.
The six crew members were found treading water and were swiftly rescued by Police Coast Guard officers.
North View Primary School said it has been in contact with affected students and their parents and will continue to monitor students' health.
According to reports, the pedestrian was taken to Tan Tock Seng Hospital, where he later succumbed to his injuries.
At present, offenders face fines of up to S$1,000 for a first offence and S$2,000 for repeat cases. If the Bill is passed, these could rise to S$10,000 and S$20,000 respectively.
Indonesian authorities began investigating the syndicate after detaining about a dozen suspects in West Java in July 2025.