A jobless man who stabbed his mother in the neck and slit her throat three years ago was sentenced to life imprisonment for culpable homicide yesterday.

Judicial Commissioner Hoo Sheau Peng agreed with prosecutors that Sujay Solomon Sutherson, 34, who has a history of paranoid schizophrenia, should be jailed for life for the protection of the public.

No caning was warranted in view of his mental condition, she said.

Last month, the judicial commissioner convicted Sujay of culpable homicide, rejecting his defence that he had knifed Madam Mallika Jesudasan, 56, in self-defence after she grabbed his hair, scratched him and tried to take his clothes off at their Bukit Batok flat.

Even yesterday, while pleading for a lenient sentence, Sujay, who defended himself in a five-day trial, maintained that his mother, whom he referred to as "the victim", wanted to have a physical relationship with him, and had told him that she was a woman who had "needs".

Speaking eloquently, he objected to sentencing submissions by Deputy Public Prosecutor Kumaresan Gohulabalan as having "no relevance" to his case.

Sujay said there was premeditation in the precedent cases cited by the DPP, but in his case, "everything happened very fast".

The DPP had argued for a life sentence, pointing to the brutal and grisly manner in which Sujay had killed his own mother, and his cunning efforts to hide his deed from his family members.

Sujay was a danger to society as he was unpredictable, lacked insight into his mental illness, and was an intelligent individual who was able to disguise his symptoms, said the DPP.

Sujay lived with Madam Jesudasan, a divorcee, and his younger brother Sunil, 28, and younger sister Sheena, 31.

On May 27, 2012, between 6.30pm and 10.45pm, he plunged a knife into his mother's neck, stabbed her again with a second knife, and then slit her throat with a third.

When his attempts to burn her body failed, he hid her under his bed and cleaned up the flat.

He feigned ignorance when Sunil got home and asked about their mother's whereabouts.

After a futile search in the area, Sunil, Sheena and their mother's brother, Mr Daniel Jesudasan, returned to the flat. Checking under Sujay's bed, Mr Jesudasan saw a pair of legs.

Sujay demanded that his family members hand over their phones, but his siblings slipped away and called the police while he scuffled with his uncle.

Yesterday, Mr Jesudasan told reporters he had expected the sentence. "Incarceration ensures treatment," he said, adding that prior to the crime, he did expect such extreme violence from his nephew.