The murder was a classic case of a crime of passion that started with the extramarital affairs Frankie Tan had engaged in and the abuse of his wife, which led the wife, Lee Chee Poh, and Tan's adoptive brother Vasavan Sathiadew to plot the killing as revenge for the victim's infidelity and abuse.
Lee Chee Poh was the only one of these four accused who escaped execution and instead received a 7-year prison sentence in a separate trial for manslaughter due to the sympathetic circumstances surrounding her life under the abuse of Tan, which drove her to the plot to kill her husband.
As she entered the study room of her banker husband Tan Tik Siah (simplified Chinese: 陈铁城; traditional Chinese: 陳鐵城; pinyin: chén tǐechéng), also known as Frankie Tan, Lee was shocked to see her 39-year-old husband lying there dead with a nylon rope around his neck, and bruises on his face and body.
Full of grief and distraught at the sight of her husband's dead body, Lee managed to wake up her neighbour and seek help.
Lee Chee Poh, who came from Malacca, Malaysia to Singapore for a better life, first met Frankie Tan sometime in the early or mid-1960s at a cabaret where she had been working for the past 10 years.
The next year, the couple moved into a two-room Housing and Development Board flat in Jalan Toa Payoh; by then, Tan was employed in the Amex bank.
At some point in the early 1970s, Tan was embroiled in stock market difficulties, and in order to help her husband, Lee raised $20,000 out of her jewellery and savings.
In early 1981, Lee Chee Poh picked up a call from a distressed Vasavan Sathiadew, who informed her of a shocking event that he discovered from his wife Amnoi.
Despite consenting to it, Lee asked the ownership of their Laguna Park flat be given to her should the divorce be granted and finalized.
Two days before the fateful night on 24 October 1984, when Lee Chee Poh went to the airport to fetch her husband, Tan once again abused and ill-treated her.
Since she served with good behaviour, and the sentence being backdated to four years earlier, Lee would be released eight months later in June 1989.
During sentencing, Justice Coomaraswamy took into consideration the tragic life which Lee had gone through with her abusive marriage and her remorse over the incident.
Lee Chee Poh later became the prosecution's key witness against the three men, who all stood trial a month after her release.
[11][12] The trial of Vasavan Sathiadew and his two Thai accomplices Phan Khenapim and Wan Phatong began on 3 July 1989.
All three men stood trial before two High Court judges – Judicial Commissioner Joseph Grimberg and Justice T. S. Sinnathuray (he was one of the two judges who sentenced the three child killers of the 1981 Toa Payoh Ritual Murders to death 6 years earlier) – in the High Court of Singapore.
She disagreed with Mr Lim's suggestion that she was compelled into testifying against the three men in the murder trial after the prosecution reduced her charge while conceding with Mr Vardan's suggestion that Tan meant a lot to her and she was being totally dependent on him, which was why she could not likely want to kill her "golden goose".
According to Phan, on that night itself, he brought along both Ah Poo and Wan after agreeing with Vasavan to assist him in the assault.
In the lift on the way down, Wan said that Vasavan paid the three of them $1,000 each; he said he initially did not accept the money but Ah Poo insisted and shoved it into his hand.
Vasavan not only denied that he had any motive or intention to murder Tan, he claimed to be suffering from acute severe reactive depression.
Veronica Sathiadew, Vasavan's 20-year-old daughter, corroborated this evidence, saying that ever since her mother's affair with her uncle Frankie Tan came to light, her father became very reserved and locked himself in his room.
There were also frequent quarrels between her parents, according to Veronica, who also added that her father would throw things around and even slapped her mother.
However, Dr Wong told the court that he did not believe his patient Vasavan when he said his intention was just to beat up, not kill, his adoptive brother.
When asked if he had come across a case or medical evidence of diminished responsibility being raised when the accused was not present at the actual killing, Dr Wong conceded that he had not.
He not only argued with Amnoi frequently, he became suspicious of her movements and also contemplated suicide twice in the first three months after discovering Tan's treachery.
[25][26] When cross-examined by Deputy Public Prosecutor (DPP) Bala Reddy, who led the prosecuting team, Vasavan denied the fact that he confessed to the police about his plan to kill Tan when DPP Reddy pointed out what he said in his oral and police statements.
In their 82-page judgement, which took 90 minutes to read, both JC Grimberg and Justice T. S. Sinnathuray found all the three men guilty of murder and sentenced them to death.
In his own words, JC Grimberg referred to the pathologist's autopsy report and said, "At some stage, one of the assailants sat upon Tan's chest, and as he struggled and fought back, a rope procured by Vasavan was double looped round his neck three times and pulled extremely tight by at least two, probably by all four, of the attackers, and secured in a tight knot.
They also pointed that after they murdered Tan, Vasavan had paid the Thais $1,000 each for their completion of the task, and even further arranged for an additional payment of $1,500 to Phan, who was set to leave Singapore for Thailand shortly after the crime, before their arrests.
As the death sentence was passed upon them in a packed courtroom, both Vasavan and Phan were reportedly calm while Wan wiped his tears.
On 23 October 1992, almost eight years after the murder of Frankie Tan, the three men – Vasavan, Phan and Wan – were all hanged in Changi Prison.