SINGAPORE - He was 16 when he robbed a woman of $30 at knife-point in a lift and stabbed her multiple times on her arm and body.

The 28-year-old woman, Ms Soh San, a manager with a telecommunications company, died from stab wounds to the chest and abdomen. She had nine stab wounds.

Twelve years later - on Nov 17, 2013 - the culprit, Gunasegaran Ramasamy, then 28, walked into Jurong East Neighbourhood Police Centre and admitted to having robbed and stabbed the victim on Oct 2, 2001.

Originally charged with murder, the charge was amended to one of robbery with hurt last year.

His lawyer, Criminal Legal Aid Scheme (Clas) Advocate Ng Shi Yang, said in his mitigation plea that Gunasegaran could have continued to keep mum on his heinous crime, but ultimately, his guilt and conscience caught up with him.

"His conscience came in the form of voices that he heard in his head, which began shortly after committing the offence in 2001, and worsening in the years leading up to his confession in 2013," he said.

On Monday (March 20), the 32-year-old was sentenced to the maximum 10 years' jail and 12 strokes of the cane for robbery with hurt. The sentence was backdated to Nov 18, 2013.

He was given a concurrent sentence of eight months' jail for drug consumption.

A district court heard that on Oct 2, 2001, Gunasegaran's sister gave him $5 to to buy some instant noodles at a shop near her block at Bukit Batok Street 21.

He then decided that he would take the chance to leave the flat to look for targets whom he could rob.

He took a knife from the kitchen, wrapped it with newspaper and tucked it at the back of his pants.

He eventually arrived at a block in Bukit Batok West Avenue 8 and saw Ms Soh who had just returned home from work at the letter box area.

Gunasegaran hid behind a wall, took out the knife and removed the newspaper wrapping before tucking the weapon under his pants near his abdomen and covered it with his shirt.

He followed the victim to the lift lobby, pressed the lift button and used his knuckle to rub against the button in a bid to remove his finger print.

After they got into the lift, he stood behind her and whipped out his knife as it was ascending and demanded for money. Ms Soh screamed for help, put up a struggle and was stabbed on her arm. She then gave him $30.

Dissatisfied, he tried to snatch her purse. When she resisted, he became angry and stabbed her repeatedly on her arm and body. She bled profusely and shouted at him to stop before collapsing onto him.

He fled by running down the stairs and washed the knife before putting it into the knife holder near the wash basin at his sister's home.

Gunasegaran had convictions in 1998, 2000, 2002 and 2006 for burglary, robbery and theft, and was last given four years and six strokes in 2011 for causing grievous hurt, breach of personal protection order and concealing stolen property.

District Judge Tan Jen Tse said Gunasegaran had committed a very serious offence and noted several aggravating factors in this case.

"I also note that you were very young at the time and was remorseful," he said.