The couple were on their way to see a medium in Chinatown when tragedy struck.
Mr Yeo Yeow Liang and his Vietnamese girlfriend, Ms Le Thi Hau, were keen to visit the Tibetan Buddhist master, as they believed Ms Le was possessed by spirits.
According to Senior Investigation Officer (SIO) Henry Chua, their motorbike journey had ended prematurely on March 3 when Ms Le suddenly "dived off" from the pillion seat and later leapt off the railings on the West Coast Highway flyover.
A coroner's inquest yesterday was told Ms Le, 24, had plunged to her death at about 3.15pm.
A calm Mr Yeo, 51, told the court yesterday: "She kept telling me she was having a headache. She was terrified and kept hearing voices. I told her not to be afraid. We were reaching our destination."
Things started to go wrong when Mr Yeo, a fishmonger at Redhill market, felt a wobble after riding up the flyover from Telok Blangah Road.
The wobble was caused by Ms Le jumping out of her seat while the motorbike was in motion.
He stopped his motorbike, turned around and was horrified to see Ms Le, who had arrived in Singapore on Feb 5, climbing the railing.
Added Mr Yeo: "I was afraid she would jump. I kept shouting to her (in Vietnamese) not to do it... (But) everything's gone." Ms Le's handprints were found at the spot from where she had jumped.
Her death was due to multiple injuries like extensive skull and pelvic fractures, bleeding and liver lacerations, which were "consistent with those expected in a fall from a height," said Dr Marian Wang in an autopsy report.
SIO Chua said Ms Le's father, Mr Le Van Bon, had told police his daughter experienced mood swings every 10 days around five months before the incident.
SIO Chua told State Coroner Marvin Bay: "She began rubbing her head constantly, as if she was having a headache. The deceased had also started to hurt herself by pounding her chest, pulling her hair and stamping her feet."
Her strange behaviour was also noticed by Mr Yeo, who said he had known Ms Le for about six years after being introduced to her in Ho Chi Minh City, Vietnam.
Mr Yeo, who already has a wife in Singapore, said: "Initially, she (Ms Le) was all right. Later on, she always looked like she was in a daze when you called her."
He said he visited Ms Le in Vietnam once every three months.
He added he had seen Ms Le, the sole breadwinner in her family, talking to herself.
In a span of three days before her death, Ms Le had twice told Mr Yeo that she wanted to end her life. Mr Yeo scolded her and reminded her she had a responsibility to her parents and seven-year-old daughter.
State Counsel Sruthi Boppana asked Mr Yeo if he had sought help for his girlfriend.
Mr Yeo said he had taken her to see a Thai Buddhist master at Golden Mile Complex on March 1, but her condition did not improve.
He did not take her to a doctor because he thought she was possessed and not suffering from mental illness.
Mr Le told police the couple were the loving sort and did not have any previous quarrels.
The police do not suspect any foul play in Ms Le's death. There were neither signs of a struggle between Mr Yeo and Ms Le, nor defensive marks on either party.
The coroner's inquiry will resume on Monday when Mr Bay will deliver his findings.
This article was first published on August 21, 2015.
Get The New Paper for more stories.