SINGAPORE — He was married with a son, but told his lover he was single.

He worked for a laundry company, but told her he owned the firm.

And when his lover, Chinese engineer Cui Yajie, began uncovering his lies, Leslie Khoo Kwee Hock strangled her to death and burnt her body over three days — until nothing was left but bits of charred fabric and a brassiere hook.

Khoo, 50, whose trial began on Tuesday (March 12), has pleaded not guilty to the charge of murdering Cui on the morning of July 12, 2016.

His lawyer Mervyn Cheong of Advocatus Law said as the trial opened that Khoo is not disputing that he killed Cui, but is arguing that his case should be considered an exception to murder on the basis of “diminished responsibility”.

After all, Mr Cheong argued, a psychiatric assessment has found that at the time of the attack, Khoo was exhibiting “intermittent explosive behaviour”, sudden outbursts that caused him to lose control of his actions.

Mr Cheong also argued that his client had faced a “grave and sudden provocation” from his lover, which had triggered a “sudden fight” — two other reasons for the exception to murder.

However, the prosecution, led by Deputy Public Prosecutor (DPP) Tan Wen Hsien, said it will prove that Khoo’s case is one of “a cold and callous murder by a charlatan… who cheated (Cui) of her feelings and her money”.

HOW THE RELATIONSHIP STARTED

Khoo was a retail outlet manager for laundry company Dryclyn Express.

Cui, who was 31 when she was killed, was a senior engineer with semiconductor firm MediaTek Singapore.

One of the first witnesses who took the stand on Tuesday was Cui’s colleague and close friend Wu Wenjuan, who testified that the duo got acquainted sometime in 2015, after Khoo saw Cui crying outside her former boyfriend’s condominium unit after a break-up.

Khoo befriended her and offered to take her home in his car.

Before they parted ways that day, he asked her to be his girlfriend, telling her that she was “such a good girl” and that her ex-boyfriend “didn’t know how to treasure” her, Ms Wu said.

Ms Wu recalled how, after the couple had been dating for a while, Cui suspected Khoo might not be single after all, when she came across a photo of him wearing a wedding band and an online article detailing how he and his wife had overcome their marital issues.

When confronted, he told Cui he had been divorced for three years, Ms Wu recounted.

The court also heard that Cui had given Khoo S$20,000 which he claimed would go towards “gold investments”.

PATTERN OF CHEATING WOMEN

He later returned Cui S$10,000 in early July 2016, using money he had received from Ms Zhang Hong, another woman with whom he was intimate. Ms Zhang thought the money was for an investment in “his family’s” laundry business.

Another of Khoo’s former lovers, known only as Karen, took the stand on Tuesday to recount how she borrowed S$10,000 from her sister and S$20,000 from her brother to “invest” with Khoo.

A third woman, Ms Zhao Chi Lan, was conned of S$10,000. She told the court she was not Khoo’s lover, but met him through a friend at a church party and believed she was investing in his laundry business.

Altogether, DPP Tan said, Khoo swindled S$65,000 from four women besides Cui.

Khoo had also misappropriated around S$24,000 in sales proceeds and franchisee fees from his employers, who did not know that he was an undischarged bankrupt, the prosecutor said.

THE 'HOUSE OF CARDS' STARTED TO CRUMBLE

Khoo’s “house of cards” began to collapse on July 11, 2016, DPP Tan said.

That day, Cui contacted Khoo’s wife — whom she believed to be his ex-wife — over Facebook's Messenger application, telling her to leave him alone.

The message read: “You hv been already divorced, so please leave Leslie Far… … away!!! Don’t cheat everybody & show off as a family any longer!!!”

The next day, Cui threatened to go to Khoo’s workplace at 3 Gul Link in Tuas to speak to his bosses.

Khoo tried to dissuade her, but she was determined.

So Khoo decided to intercept her at Joo Koon MRT Station, the station nearest to his workplace. There, he told her he would take her to see his supervisor and she boarded his car.

But instead of taking her to his workplace, he drove her to a secluded spot at Gardens by the Bay and strangled her as she sat in the front passenger seat, until she stopped moving.

He then bought charcoal and kerosene from two shops along Kranji Road and headed to Lim Chu Kang Lane 8, where he placed her body under a metal canopy and burnt it over three days.

During those three days, he would visit the site occasionally to feed more charcoal and kerosene to the fire.

DPP Tan said: “By the accused’s own account, even if he did not strangle her to death, he would have killed her by burning.”

It was only on the afternoon of July 14, 2016 — after Cui had not turned up for work for three days — that her worried colleagues made a police report about her disappearance after calling her parents and visiting her flat.

The police later established that Khoo was the last person who had interacted with Cui, and Khoo was arrested on July 20.

NO EVIDENCE OF PROVOCATION

Cui’s body was never recovered.

Only some of her hair, bits of fabric and a brassiere hook remained, but it was enough for investigators to confirm that Cui was at the scene where she was burnt, DPP Tan said.

Countering the defence from Khoo’s lawyer, DPP Tan argued: “There is no evidence — apart from the self-serving claims of the accused — that the deceased had provoked him or that a fight had broken out between them.

“Even if she were scolding him or hitting him on his forearm as he claimed, this is insufficient to amount to grave and sudden provocation… The accused’s response to any purported provocation or sudden fight… is disproportionate by any measure."

She pointed out, too, that another psychiatrist — Dr Kenneth Koh, a senior consultant with the department of general and forensic psychiatry at the Institute of Mental Health — found that Khoo does not suffer from intermittent explosive disorder.

If convicted of murder, Khoo could face the death penalty or be jailed for life.