Two attackers almost got away with brutally slashing a man.
But police managed to arrest them, thanks to DNA samples taken from a taxi they were in when fleeing the scene.
Part-time waiter Peter Nicholas Hamsha and Leow Zheng Yang attacked businessman Loo Kean Boon, 38, with knives at Club ION at Balmoral Plaza in Bukit Timah Road around 2am on Aug 10 last year.
Police were initially unable to establish the slashers' identities as none of the witnesses could identify the pair.
The image resolution of closed-circuit television footage was also too poor to make out who the attackers were.
But police managed to trace the taxi later that day and took DNA swabs from it. The samples were analysed and a hit was established with Hamsha's DNA.
Police tracked down the duo and arrested them on Oct 16 last year.
Hamsha, 22, was jailed for 41/2 years and ordered to receive six strokes of the cane on Wednesday, after he pleaded guilty to one count each of causing grievous hurt with a weapon and being a member of an unlawful society.
Police were initially unable to establish the slashers' identities as none of the witnesses could identify the pair... But police managed to trace the taxi later that day and took DNA swabs from it. The samples were analysed and a hit was established with Hamsha's DNA.
The case involving 21-year-old Leow, who is jobless, is pending.
Deputy Public Prosecutor Li Yihong said Hamsha and Leow were members of the same gang.
Some time in the middle of last year, Leow saw Mr Loo at St James Power Station and accused him of being part of a group that had beaten Leow up over a staring incident. Leow decided to seek revenge even though Mr Loo denied taking part in the attack.
Mr Loo, who runs a pet grooming shop, was in Club ION around midnight on Aug 10 last year when a member of Leow's gang spotted him.
Solving crimes with DNA
DNA can be extracted from a person's bodily fluids like blood, semen and saliva, as well as skin and hair, said Assistant Professor Guillaume Thibault from Nanyang Technological University.
Speaking to The Straits Times yesterday, the biochemist from the university's School of Biological Sciences added: "Each person's DNA is unique. No two people have the same DNA, unless they are identical twins.
"So, when the police manage to pinpoint an offender to a crime scene, it's pretty accurate."
However, Prof Thibault said that one must be careful when collecting DNA at crime scenes to prevent cross-contamination. "All DNA can be contaminated or can degrade over time. So, all samples must be retrieved as soon as possible."
The DNA database for criminals was set up in Singapore in 2004 at a cost of $4.2million.
The samples for Singapore's database are collected by police officers trained to gather such data, and then recorded and analysed by the Health Sciences Authority (HSA).
These are used to check for matches with evidence collected at crime scenes.
The HSA said on its website: "The advent of DNA profiling methodology in 1985 has had an enormous impact on the ability of crime laboratories to uniquely identify individuals by testing a variety of samples.
"Since then, the combination of incorporating modern genetic and molecular biology techniques by crime laboratories and the establishment of national DNA databases has resulted in greater success in the identification of criminals."
The gang member alerted Leow, who called Hamsha, and the two men armed themselves with knives before making their way to the club.
DPP Li said: "(Hamsha) snuck up to the unsuspecting victim from behind by crouching down low. (He) then quickly stood up and slashed the victim twice on his head and face, catching the victim completely unawares. (Leow) then joined in and slashed the victim once on his face."
The attackers then ran off, hailed a taxi and fled.
Mr Loo was unconscious when he was rushed to Tan Tock Seng Hospital. He sustained injuries including facial wounds that led to permanent disfiguration, a deep 20cm cut from the back of his head to the right side of his neck, and a wound on his right ring finger, with an irreparably damaged nerve.
Leow fled to Johor Baru on Aug 10 last year while Hamsha joined him there the following day. They returned to Singapore two weeks later when they ran out of money.
They were arrested about two months later.
For voluntarily causing grievous hurt with a weapon, Hamsha could have been jailed for up to 10 years and fined or caned.