Singapore woman gets 18 years’ jail for killing adoptive father over HDB flat ownership dispute

Tan Qiu Yan, 33, was sentenced on 14 July 2025 to 18 years’ imprisonment for killing her adoptive father with a chopper in their Sengkang flat. The court heard that Tan, who suffered from a delusional disorder and schizoid personality disorder, acted under diminished responsibility. Despite her mental condition, the High Court described the act as "a shocking and brutal" attack on the man who had cared for her since childhood.

Victim fatally attacked after months of family tension

Tan’s adoptive mother, diagnosed with lung cancer in 2019, passed away in August 2022, according to local media outlet Lianhe Zaobao. Before her death, she had promised to leave her share of the HDB flat at Block 190A Rivervale Drive to Tan. As the flat was held under joint tenancy, ownership transferred fully to her husband, Tan Ah Bang, after her death. Tensions flared between father and daughter during the funeral wake. Disagreements over financial assets and the flat’s future ownership escalated into frequent quarrels. At one point, the father told Tan she had to move out. He later relented and promised to transfer ownership to her, but doubts remained in Tan’s mind. She began suspecting that her father would retain full ownership and force her out, intensifying her paranoia and feelings of insecurity.

Chopper bought with intention to kill

A few days after the funeral, Tan bought a sharp, large chopper from a supermarket, deliberately selecting it with the intent to kill her father. She later practised swinging the chopper through the air and slicing a banana, confirming to herself that the weapon would be "effective." Tan continued to press her father about sharing ownership of the flat. When he refused again, scolding her during one argument, she became convinced he was scheming against her. She contemplated using scissors to attack him but stopped herself. Still, the thought of becoming homeless continued to plague her.

Attack carried out after final confrontation

On the morning of 3 November 2022, Tan overheard her father on a phone call, claiming he could not speak as his daughter was nearby. Interpreting this as further proof of a plot, she contacted a law firm about adding her name to the flat’s title deed but was told it was not possible. Later that day, after receiving a condolence card from a hospital, her grief deepened. She cried, then resumed practising with the chopper in her bedroom. By evening, she confronted her father one last time. While he was scrubbing her work uniform, she asked if he would agree to 50-50 ownership. He angrily refused. Tan resolved to carry out the attack. After dinner, she waited for him to take a shower. Hearing the water running, she removed her glasses and waited outside the toilet. When her father opened the door at around 8pm, she swung the chopper at him, aiming for his neck.

Attack lasted 10 minutes, described as 'horrific'

The court heard that Tan hacked her father five to 10 times initially. He tried to speak and grabbed her hair, even biting her finger in the struggle. As he continued to hold on, she struck him about 10 more times until he was motionless. She then sat cross-legged, facing him, and continued attacking for another 30 slashes, eventually stopping only due to exhaustion. The entire attack, by her estimate, lasted 10 minutes. She later cleaned the toilet, disposed of her bloodied clothes, listened to music, and looked at old family photos. At 5am the next day, she contacted the police to report that her father had died, leading to her arrest.

Mental health and legal defence

An autopsy determined the cause of death as bleeding from incised neck wounds. Photos presented in court showed extensive injuries. The Institute of Mental Health (IMH) diagnosed Tan with delusional disorder of a persecutory type, alongside schizoid personality disorder. Though she qualified for a partial defence of diminished responsibility, she was deemed fit to plead. The IMH noted that if untreated, her psychosis could worsen and increase the risk of future violence. Deputy Public Prosecutor Sheldon Lim called for life imprisonment, warning that Tan posed a "catastrophic risk" to the public without proper treatment. He noted that Tan had no family support system and might stop medication after release.

Judge weighs mitigating factors and risk

Defence lawyer Daniel Koh requested a sentence of five to seven years, citing Tan’s cooperation, isolation, and improved behaviour during custody. He said Anglican Care Centre was prepared to support her reintegration, and a Prison Fellowship pastor had also offered her support. Justice Mavis Chionh considered whether Tan met the criteria for life imprisonment under culpable homicide not amounting to murder. She concluded that Tan did not fulfil the second condition: being a person of unstable character likely to reoffend. The judge cited Tan’s lack of previous offences or violent history, and the IMH report stating her mental collapse was rooted in intense grief. A January 2025 psychiatric assessment also found that Tan had gained partial insight into her condition.

Case highlights mental illness, isolation and grief

Justice Chionh noted that Tan’s fears of homelessness had been reinforced by her father’s words and actions, even if unintentional. She remarked that while the father may have eventually relented, "the point is that her conduct was founded on fact, not fantasy or fiction." Nevertheless, the violence she inflicted was "entirely out of proportion to the perceived threat," the judge said. Photos submitted to the court showed the severity of the injuries and the extent of the attack. Tan inflicted fatal wounds using a sharp chopper on a man who had cared for her throughout her life, the judge added. The court sentenced her to 18 years’ imprisonment, balancing the mitigating factors with the gravity of the offence. Tan remained silent throughout the proceedings, listening through a Mandarin interpreter with her eyes closed, showing no outward emotion.