A jobless man who stabbed his mother in the neck and slit her throat with three different knives three years ago was yesterday found guilty of culpable homicide following a five-day High Court trial last month.

Sujay Solomon Sutherson, 34, who has a history of paranoid schizophrenia, did not dispute killing Madam Mallika Jesudasan, 56, an administrator in a public relations firm. He claimed he had knifed his mother in self-defence because she grabbed his hair, scratched him and tried to take his clothes off at their Bukit Batok flat after he dismissed her request for money.

Sujay's account was rejected yesterday by Judicial Commissioner Hoo Sheau Peng.

The judicial commissioner said that even if she accepted his account of how Madam Jesudasan had attacked him, he could not claim self-defence, which can be pleaded only when an accused person is faced with assault that is likely to cause death or grievous hurt.

After the first stab, Sujay knew that his mother would probably die from the wound; so when he stabbed her the second time, he could not reasonably have regarded her to be a danger, she said.

Sujay will be sentenced next month. He faces either life imprisonment with caning or up to 20 years' jail and caning or fine.

Madam Jesudasan, a divorcee, was last seen alive on May 27, 2012, by daughter Sheena, 31, who left the flat at 6.35pm, leaving her mother alone with Sujay.

When Madam Jesudasan's younger son Sunil, 28, returned home at about 10.40pm, he realised that his mother was not at home. When asked, Sujay said he did not know where their mother was.

After a futile search for Madam Jesudasan in the neighbourhood, Sunil, Sheena and their maternal uncle Daniel Jesudasan returned to the flat. When Mr Jesudasan checked under Sujay's bed, he saw a pair of legs.

Realising that his mother's body had been found, Sujay demanded that his family members hand over their phones. The siblings managed to slip away and call the police.

When police officers arrived, Sujay was still struggling with his uncle in the living room.

After his arrest, Sujay told police that in self-defence, he plunged a knife through her neck, stabbed her again with a second knife, then slit her throat with a third knife.

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