Tan Chee Wee was born on September 5, 1973, in Kangar, Perlis, Malaysia. He moved to Singapore in 1998 to work and lived in a workers’ dormitory with his wife, Goh Ai Hoon, while employed as an assistant store supervisor. The couple had one child who lived with his wife’s sister in Malaysia. Tan was known to have a long-standing friendship with Ler Lee Mong, the husband of the victim, and regularly played mahjong with him and other acquaintances.

Financial stress played a significant role in Tan’s life. By early 2003, he faced mounting debts of approximately S$11,000, accrued from gambling on football matches, mahjong, and loans from moneylenders and colleagues. Despite earning a modest income of S$1,155 a month, he struggled to cover expenses, including a car shared with his wife to visit their child in Malaysia.

On the evening of January 9, 2003, Tan Chee Wee entered the flat of Thabun Pranee, a 26-year-old Thai citizen married to Ler Lee Mong, in Chai Chee, Singapore. Tan, who was acquainted with both Ler and Thabun, initially called the flat multiple times, reportedly checking to see if anyone was home. When Thabun answered the door, he convinced her he needed to use the toilet and gained entry.

Once inside, Tan proceeded to rob the flat, taking cash and gold jewelry. Thabun attempted to resist, and Tan restrained her by tying her hands. A struggle ensued, during which Tan raped her and attempted to control the situation with a knife, inflicting injuries in the process. Thabun managed to grab the knife, leading Tan to strike her with a hammer, resulting in severe blunt force trauma to her head. She fell unconscious, and Tan left the flat, leaving the door open. According to his statements, he believed Thabun was still alive and had no intention to kill her, though the severity of her injuries proved fatal.

Investigators found Thabun’s body later that evening when her husband returned home and discovered bloodstains across the flat. Forensic examination confirmed head injuries and a stab wound to the neck as causes of death. Approximately S$500–600, a Rolex watch, and gold accessories were missing, indicating robbery as a motive.

Police investigations quickly identified Tan as a suspect, partly through phone records and his connections to the victim’s husband. Tan was arrested on January 10, 2003, just six hours after the investigation began. Evidence recovered included stolen items, weapons, and tools used in the crime. Despite initially denying the murder, Tan admitted during interrogation to killing Thabun during a robbery.

Tan’s trial commenced on August 18, 2003, at the High Court of Singapore, presided over by Justice Woo Bih Li. The prosecution argued that the murder was premeditated, motivated by robbery, and that Tan’s violent actions during and after the crime demonstrated intent to eliminate the victim as a witness. The defense claimed self-defense and suggested the possibility of another person committing the murder after Tan left. Tan also argued that he did not intend to kill Thabun and that he left the door open so she could seek help.

The court rejected Tan’s defense, describing his actions as “violent and merciless”, and concluded that his conduct showed clear intent to cause death. On September 29, 2003, Tan was convicted of murder and sentenced to death by hanging. Charges of rape and robbery were stood down during proceedings but factored into the context of the case.

Tan appealed the sentence, arguing the same defenses, but on November 17, 2003, the Court of Appeal unanimously rejected his appeal, confirming both his conviction and the death sentence. On June 11, 2004, at the age of 30, Tan Chee Wee was executed by hanging at Changi Prison, Singapore.