A car could not be stopped by a security barrier at the Woodlands Checkpoint, and the authorities are now looking into how this could have happened, even as it emerged that drugs could be behind the breach on Saturday.
The police explained on Sunday why it took five hours to nab the suspect, saying that although they had called him on his mobile phone, he threw them off the scent by "driving across various parts of Singapore and switching to another vehicle".
"This was a determined criminal; he clearly was out to evade arrest," police director of operations Lau Peet Meng said in a media briefing on Sunday. "We are not looking for someone who is just walking down Orchard Road."
On Saturday, the suspect - a 64-year-old Malaysian who has Singapore permanent residency - drove his Singapore-registered Mercedes-Benz sedan into the checkpoint for immigration clearance at 3.53pm.
He was stopped for a boot check at 4.02pm, but suddenly drove away with the boot still open. He mounted a kerb to overtake another car as he dashed for the exit, said the Immigration and Checkpoints Authority (ICA).
An auxiliary police officer "smashed" the right window of the 24-year-old car's back passenger seat, and a security barrier near the exit was raised, the ICA said in a statement.
The barrier punctured both the front tyres of the vehicle, but did not stop the car from driving over it and speeding away, it said.
It was the first time the barrier failed to stop a car, ICA Deputy Commissioner Aw Kum Cheong said on Sunday, adding that the authority is reviewing why the barrier was ineffective.
Installed in 2006, the 30cm-high barrier was "crash-tested" during installation, where it stopped a pickup truck, said Mr Aw. It also barred an unauthorised car from leaving the checkpoint in 2012.
The ICA would not say how much the barrier system cost.
Meanwhile, the police also revealed that the driver is under investigation for drug offences, as a "package suspected to contain drugs" was found.
They would not say where and how the package was found, or how it was connected to the checkpoint breach.
But they added that four men associated with the suspect are "assisting the authorities in the investigation", police parlance for people who were questioned but not named as suspects yet.
Two are Singaporeans picked up by the police, and the other two are Malaysians who were stopped from leaving Singapore by car and bus.
Police also declined to say how the suspect, who uses the Woodlands Checkpoint almost daily - according to the ICA - is linked to the four men, citing ongoing investigations.
The latest breach comes barely two months after a similar incident on Jan 17 involving Malaysian teacher Nurul Rohana Ishak, 27, who slipped past immigration officers at Woodlands Checkpoint. She was arrested three days later and now faces charges, including that of criminal trespass.
Hours after the second breach, a video - which showed the car, with the right window of its rear passenger seat intact, taking less than 20 seconds to drive over the barrier - was posted online.
The ICA did not dispute the authenticity of the video, which appeared to have been recorded using a smartphone off a computer showing the CCTV recording.
But the authorities warned that the video leak is now under an Official Secrets Act investigation, and the clip should not be circulated.
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