2022 Sengkang killing: Woman hacked adoptive dad to death over 'delusions' that he would kick her out of flat

Just months after the death of her adoptive mother, 32-year-old Tan Qiu Yan devised a plan to kill her remaining parent.

She suffered from a delusional disorder and believed he would kick her out of their flat and leave her homeless, prosecutors said.

After dinner one night, she attacked him with a chopper in their Sengkang flat and killed him.

She hacked at his neck at least 45 times over the course of the 10-minute attack.

Tan was sentenced to 18 years' jail on Jul. 14 for culpable homicide not amounting to murder.

The dispute

According to court documents seen by Mothership, she was adopted by a couple, Koh Li Hua and Tan Ah Bang, when she was less than a year old.

In 2019, Koh was diagnosed with lung cancer.

Before she died on Aug. 29, 2022, she promised her daughter that she would leave her share of the flat to her.

But arguments between father and child soon began.

During Koh's wake, Qiu Yan and her father quarrelled over Koh's financial assets multiple times.

On one occasion, Ah Bang got angry and told his daughter that she had to move out.

She retorted that her mother had left the flat to her and began to cry.

Ah Bang relented, and promised his daughter that he would transfer the whole house to her.

Purchased a weapon

But Qiu Yan did not trust her father.

She was afraid that he would chase her out of the house after Koh's wake, so he could have the whole house to himself.

On Sep. 4, 2022, a few days after the funeral, she purchased a chopper from the FairPrice outlet at Nex: the biggest one she could find.

She intended to use the 18cm-long weapon to kill Ah Bang, if he did not keep his promise.

After the funeral ended, Ah Bang made an appointment with his lawyers to settle matters pertaining to Koh's estate.

They subsequently realised that Ah Bang had automatically become the sole owner of the flat, after Koh's death.

This was because Koh and her husband had co-owned the flat.

Suffered delusions

Qiu Yan panicked. She believed her father would kick her out of the flat.

On Nov. 2, 2022, she asked him when he was free to go to the Housing and Development Board (HDB) office to add her as a co-owner.

But he demurred, and they began to quarrel.

Ah Bang scolded her for not telling him that she'd received her mother's Central Provident Fund (CPF) monies, and for going to check on the status of Koh's investment.

He also scolded her for meddling with household matters, and for stopping him from throwing Koh's belongings away.

In the midst of the argument, Ah Bang said he would not leave her the flat after his death.

He threatened to donate it instead.

Plotting the death

At that moment, Qiu Yan considered killing her father with a pair of scissors on the table.

She decided against it as she did not think they would be sharp enough. But she continued to contemplate his death.

One thing she considered was to merely injure him, to scare him into transferring ownership of the flat to her.

But she dismissed this in the end, as she believed she would be sent to prison, while Ah Bang would still get to keep the flat.

After lunch the next day, she began to practise using the chopper.

She also tested its sharpness on a banana.

The attack

Qiu Yan decided to give her father "one last chance".

On the afternoon of Nov. 3, 2022, she went to the bathroom, where he was scrubbing her work uniforms.

She asked if he would share ownership of the flat 50-50 with her.

But he refused, and told her not to bring up the matter anymore.

She decided to kill him then. To catch him by surprise, she plotted to do so in the common toilet.

She decided she would hack at his neck, so he would "definitely die".

After dinner that evening, she waited for him to take a shower, and retrieved the chopper.

The moment he opened the door, Qiu Yan swung the chopper at his neck.

He tried to say something to her, but she ignored him.

Over the next 10 minutes, she hacked at his neck at least 45 to 50 times.

She continued to hack at him even after he fell backwards and became motionless.

By the end of her onslaught, the chopper had become blunt, and the blade was chipped.

She cleaned up the mess, changed into new clothes as she was covered in blood, watched anime, and looked through photos of herself as a child with her parents.

Finally, she called the police.

"My father passed away at home. Can police come please," she said over the phone.

Sentencing

In their submissions, the prosecution said that Ah Bang "cared deeply for his daughter".

"From the time she entered his family, he and his wife took care of her. He saw tirelessly to her every need.

On the day of his death, he spent his afternoon washing her work uniform, and his evening cooking dinner for her before they ate together."

The prosecutors acknowledged that Qiu Yan suffered from delusional disorder and schizoid personality disorder.

However, she had not accepted nor received any treatment for her condition, they said.

As such, she "poses an extreme danger to the public", they said. They called for a life sentence.

But Justice Mavis Chionh noted that Qiu Yan did not have a history of offending, or of unstable or violent behaviour.

She referenced an Institute of Mental Health (IMH) report that said a major factor contributing to Qiu Yan's mental state was her grief from losing her mother.

As of January 2025, the psychiatrist found that Qiu Yan "appeared to have gained at least partial insight into her condition", the judge said, according to CNA.

She sentenced Qiu Yan to 18 years' jail, calling it a "shocking and brutal act of violence" against her adoptive father.

Related stories

Top image from Shin Min Daily News/Facebook and Nixon Tan