SINGAPORE — The man who killed his twins in 2022 was sentenced to 14 years' jail after he admitted to strangling the boys and submerging their faces in a canal to ensure they were really dead.

Xavier Yap Jung Houn, 49, believed that killing his 11-year-old sons, who were diagnosed with autism spectrum disorder, would take away his wife's burdens.

He also feared that no one would take care of the boys — Aston Yap Kai Shern and Ethan Yap E Chern — after he and his wife died, and was worried that the twins would be bullied by others.

After killing them, he attempted to end his own life by stabbing his stomach, chest and back with an ice pick. He also hit his head with a tree branch and a rock.

Xavier Yap was sentenced to seven years' jail on each of the two charges of culpable homicide not amounting to murder.

He carried out his plan to kill the boys on Jan 21, 2022. He drove them to a playground in Greenridge Crescent, which is near his condominium in Toh Tuck Road.

The boys played there for around 10 minutes before he carried them one by one into a nearby canal.

He then picked up a stick and pressed it hard against Ethan's neck. When the stick broke, he strangled him by placing his forearm across the boy's neck and pressing down hard.

Ethan initially struggled, but he eventually stopped moving. Xavier Yap then placed him on the ground with his face submerged in the water of the canal.

He then turned his attention to Aston, who had been standing quietly a few metres away while his brother was being strangled.

Xavier Yap tried to strangle Aston by placing his forearm across his son's neck, but he was not strong enough and both fell to the ground.

While Aston was lying on the ground face up, Xavier Yap strangled him and continued to apply force to his neck until he was motionless.

He then submerged the boy's face in the canal water.

On Tuesday (Aug 15), Xavier Yap stared blankly into space as the facts of the case were read out in court.

The prosecution said the victims were formally diagnosed with global developmental delay and autism spectrum disorder in 2017. They were suspected to have autism spectrum disorder since they were two years old.

While it was recommended that the twins be placed in a special education school, their mother had difficulty accepting her sons' conditions.

Instead, the victims were enrolled in Primary 1 in a mainstream school at age nine, while they were still unable to speak.

The court heard that Xavier Yap had a good relationship with his sons, and did not usually discipline them with physical force. He was also more involved in their studies after they enrolled in the school.

Sometime in 2019 and 2020, he started to worry more about his sons' future. He was saddened that his wife was unable to accept their conditions.

The prosecution said that the twins' mother would often get angry with the boys, which also concerned their father.

Xavier Yap developed suicidal thoughts and purchased an ice pick in December 2021.

At the start of 2022, he started harbouring serious thoughts of killing his sons and himself after he noticed that his wife was increasingly frustrated and depressed because of the boys' conditions.

Xavier Yap felt that his wife had given up on them, and he believed that killing them would take away her burdens.

Seeking a sentence of 14 to 20 years' jail for the twins' father, the prosecution on Tuesday said a tough stance should be taken against offenders who use violence on defenceless young victims.

"While the accused's mental state at the time of the offences should be a factor in calibrating sentence, his illness is not a blanket excuse for his actions.

"This is especially so considering that the accused caused the death of two young victims," said the prosecution.

The defence sought a jail term not exceeding five years on each charge, and for the sentences to run concurrently.

In court, Xavier Yap's lawyers read out a letter he had written. In it, he said he believed that he could end his sons' suffering by killing himself and taking them "along with (him)".

He also said his major depressive disorder was exacerbated by his wife's expectations of the boys — that they would behave like normal children.

She had set out unrealistic expectations by physical punishments and scoldings, he said in the letter.

Xavier Yap, whose 80-year-old mother was in court, also said that his condition was further aggravated when he learnt that his wife was cheating on him.

With him and the twins gone, he believed his wife could carry on with life with her "newfound love".

Xavier Yap, who was represented by Patrick Nai, Choo Si Sen and Choo Yean Lin from Tan Lee & Partners, and Mr Muhammad Razeen Sayed Majunoon from Advance Law, also claimed in his letter that his wife was "not even saddened by the demise of her two sons, as she started inviting her lover to stay at (their) house".

"As a mother, she even threw away her two sons' belongings. She has crossed the boundary that I could no longer tolerate," he added in the letter.

In sentencing Xavier Yap, Justice Vincent Hoong noted that the twins' father had major depressive disorder when he killed his sons.

He added that the boys were particularly vulnerable as they were not just young children, but also had autism spectrum disorder.

While it was a tragic case, the judge said Xavier Yap had betrayed the deep trust that a child has in his parent. Instead of caring for them as a parent would, he killed them.

Those convicted of culpable homicide not amounting to murder can either be jailed for life and caned, or jailed for up to 20 years and fined or caned.

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This article was first published in The Straits Times. Permission required for reproduction.