The 46-year-old private bus driver was giving his defence on a charge of murdering Ong Pan Hui, 15, the China-born daughter of his former wife, Madam Xiu Yanhong, 39, at a Marsiling flat last Oct 20.

Ong was still sitting by the body of the dead teenager when the police arrived at the scene. He was fiddling with his phone and was reeking of alcohol.

He said on Monday - the fourth day of his murder trial - that he had earlier called his wife that evening saying he wanted to see their four-year-old son.

His wife told him the boy was at her Tanjong Katong Road shop, and that he could see him there.

'As I was unable to see my son, and yet she still said those words to provoke me, I was very angry,'' he said in Hokkien through a Chinese interpreter.

Ong said he then tried to call his wife a few times without success.

He went home and rode to Block 24 Marsiling Drive to ask Pan Hui why she had beaten and threatened his son.

He also wanted to find out if she was happy with her Singapore identity card and school results.

After getting into the flat, Ong queried Pan Hui about the son's beatings and the numbers of his ex-wife's two shops.

He said Pan Hui was very angry and blamed the couple for always disturbing her after their quarrel.

He alleged that after turning off her computer, she tried to reach out for something, and raised her voice.

He became frightened, and in a fit of anger, grabbed and pushed her to the floor.

She struggled. He pressed her on her neck and head and asked why she was treating him so badly. Even though she said she had regarded him as her father, Ong was still unhappy and upset at the way mother and daughter had treated him after he had helped them get their identity cards.

He said he was under a lot of pressure and did not know why he strangled his stepdaughter. He was also stressed out with his wife's misbehaviour at work with different guys escorting her home each night.