He was married, an undischarged bankrupt and the manager at a laundry outlet. But Leslie Khoo Kwee Hock told a woman 17 years his junior that he was single and the heir of the family laundry business.

Khoo also got Ms Cui Yajie to hand him $20,000 to invest in gold.

Their rocky relationship came to a grisly end when he strangled the Chinese national and burned her body at Lim Chu Kang Lane 8.

When the 50-year-old led police to the scene after his arrest, he smiled and said there was "nothing left", the High Court heard on the first day of his murder trial yesterday.

Khoo, who faces the possibility of hanging, does not dispute that he killed Ms Cui, a 31-year-old senior engineer with a semiconductor company, on the morning of July 12, 2016.

His lawyer, Mr Mervyn Cheong, told the court that Khoo would be relying on diminished responsibility, sudden fight, and grave and sudden provocation to establish that the killing did not amount to murder.

However, Deputy Public Prosecutor Tan Wen Hsien painted a picture of Khoo as a serial swindler who cheated several woman of their money and feelings by asking them to invest in his business.

DPP Tan has lined up Khoo's past lovers and "investors" as witnesses to establish the case that he had killed Ms Cui because she was closing in on his lies.

In the days leading up to her death, Ms Cui contacted Khoo's wife - whom she believed he had divorced - and told her to leave him alone.

She also demanded that Khoo return the $20,000 she had entrusted to him for investment and threatened to confront his bosses at work.

"The accused saw the house of cards he built crumbling," said the DPP, adding that Khoo wanted to stop Ms Cui from "setting off a train of inquiry" against him.

In allowing the testimony of these witnesses, Judicial Commissioner Audrey Lim said there were no eyewitness to the killing and the case rested on Khoo's account of events and circumstantial evidence.

The pair entered into a relationship in 2015 "founded on a bed of lies", said DPP Tan.

At first, Khoo, who has a son, told Ms Cui he was single, but when her suspicions were later roused, he told her he was divorced. He was a retail outlet manager for a laundry company but told her that it was his family business.

As time went by, the lovers had frequent quarrels over Khoo spending too much time with his "ex-wife" and son, and the money Ms Cui "invested".

Khoo's wife then confronted him for cheating on her, after Ms Cui sent her a Facebook message to stay away from him. In the early hours of July 12 that year, after Ms Cui threatened to speak to his bosses, he picked her up from Joo Koon MRT station in his car to take her to meet his supervisor, said the DPP.

But instead, he drove her to a secluded location at Gardens by the Bay, and in the parked car, he strangled her in the front passenger seat

Khoo admitted that he decided to burn her body and bought significant quantities of charcoal and kerosene from two shops at Kranji Road. He then went to Lim Chu Kang Lane 8, placed the body under a metal canopy and burned it.

Over the next three days, he returned to add more fuel and ensure that the body was burning well.

When Ms Cui did not turn up for work by July 14, her colleagues lodged a police report.

Khoo was arrested on July 20.

Clumps of hair, pieces of fabric similar to the dress Ms Cui was last seen in and a bra hook were all that were recovered from the scene.

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