SINGAPORE - A man was arrested on Friday morning (July 9) for his suspected involvement in a case of armed robbery, just 11 hours after the heist.

The 30-year-old Singaporean allegedly went to a licensed moneylender along Bukit Batok Street 31 at about 7pm on Thursday and showed a woman working there a handwritten note.

Two notes that were later seized by the police were shown to the media.

The first note read: "Don't panic. Don't shout. This is a robbery. Fill up the bag with money. You have two minutes. Or else!"

The second note read: "This is a robbery. Don't shout. Don't panic. Put all the money in the bag and nobody will get hurt."

The man had purportedly indicated he had a knife in his bag.

The victim complied with the man's instructions and handed him $22,000 in cash, whereupon he fled the scene.

But just 11 hours later, the suspect was arrested along Lorong 8 Geylang, despite having taken several steps to mask his identity and cover his tracks.

About $18,500 in cash, the two demand notes and a bag were seized by the police.

At a press conference on Friday afternoon, the police said they were alerted to the incident at about 7.15pm on Thursday, and had worked overnight to identify the man and arrest him.

Key to cracking the case was footage obtained from nearby police CCTV cameras (polcams), said Commander of Jurong Police Division, Assistant Commissioner of Police Shee Tek Tze.

The police have relied on tens of thousands of polcams installed islandwide since 2012 to solve a variety of cases, from theft to loanshark harassment.

About 50 officers from the Jurong Police Division, Criminal Investigation Department, Police Intelligence Department, Police Operations Command Centre, and Public Transport Security Command were involved in the case.

The police are still working to recover the rest of the loot and the knife that was purportedly used in the robbery.

The suspect is believed to have acted alone. He is expected to be charged on Saturday with armed robbery.

If convicted, he faces up to 14 years' jail and 24 strokes of the cane.

AC Shee said the suspect had covered up his features with a hat and long-sleeved top, and had avoided leaving any trace of evidence at the crime scene.

But the man was still caught with the aid of polcams, which AC Shee said were instrumental to cracking the case.

The man's actions "did not stop the police from pursuing available leads to quickly identify and arrest him within 11 hours of the reported crime", said AC Shee.

"This case exemplifies the relentless commitment from the Singapore Police Force in pursuing such criminals to bring them to justice."