Eight years after a man dressed as a woman attempted to rob the bank he was guarding, Certis Cisco auxilliary police officer Rosli Mohamad Sa'ad still remembers the stubble on "her" chin which gave the robber away.

Mr Rosli, 54, was the lone security guard at the City Plaza branch of United Overseas Bank (UOB) in November 2008 during the attempted robbery - a rare crime in Singapore.

Earlier this month, a robber made off with $30,000 from a Standard Chartered Bank branch in Holland Village - thought to be only the fifth bank robbery, or attempted one, in Singapore in the last 12 years.

The suspect, Canadian David James Roach, was nabbed in Thailand after more than 72 hours on the run.

The case brought back memories for Mr Rosli who had to undergo psychiatric assessments after foiling the crime in 2008.

On Nov 10 that year, a tall "woman" dressed in black entered the UOB branch in Geylang Road. Her odd dressing - a headscarf, coat and gloves - tipped off Mr Rosli, then a 20-year Cisco veteran, that something was not quite right.

Signalling to bank staff who were replenishing an ATM to stop what they were doing, Mr Rosli turned his attention to the suspicious character.

"I was very close to him when he entered the bank, I could see his stubble," he recalled.

The guard followed as the customer headed straight to one of the counters, placed a green paper bag on it and told the bank teller to put money into the bag.

"(The robber) threatened the bank teller and said there was a bomb inside," said Mr Rosli. "She" also warned the guard not to be a hero.

When the robber fumbled with his mobile phone, Mr Rosli took the chance to wrestle him to the ground and, with the help of bank staff, held him down until police arrived.

The robber, Ismail Shaikh Ahmad, was sent to prison for eight years and received eight strokes of the cane.

The "bomb" in his bag turned out to be nothing more than a plastic container, paper boxes and a can of air freshener.

Mr Rosli, who was later commended by the police for his alertness and bravery in foiling the robbery, downplayed what he did as part and parcel of his job, despite the rarity of such crimes.

He added: "If you do this kind of job... you have to face these threats, but you don't know when it's going to happen so you have to be vigilant all the time."