A technical support officer, who wanted to get the attention of a lecturer at Ngee Ann Polytechnic, spiked her water with a "love potion" that he had bought online in the hope that she would fall for him.
But all it did was leave her with a dry throat and an inability to think clearly or sleep.
Wong Fook Hiong, who is married, was caught when the woman secretly filmed him spiking the drink with the concoction.
It was a combination of a sedative meant for animals and an anti-psychotic drug.
The 43-year-old was yesterday given the maximum fine of $1,500 for doing an act so negligently as to endanger life on Jan 12 last year.
Wong admitted to pouring a mixture of xylazine and haloperidol - both poisons - into her water bottle at the polytechnic in Clementi Road.
Assistant Public Prosecutor N. K. Anitha said that some time in November 2014, the 30-year-old lecturer drank some water from her bottle and found that it tasted bitter. She immediately spat it out.
After this happened a few times, she decided to place her mobile phone in video recording mode at her desk.
On Jan 12 last year, she left at about 5.30pm before returning at about 8pm.
She checked her phone and noted that Wong had walked to her desk at about 6.40pm and poured the substance from a vial into the bottle of water on her desk.
He shook the bottle and placed it back in its original position.
She made a police report the next day and Wong was arrested with a glass vial of unknown substance. On analysis, the water and the vial were found to contain the two poisons.
Xylazine is a sedative, analgesic and muscle relaxant used in veterinary medicine. The reported effects in humans include drowsiness, disorientation, lethargy, hypotension, a slow heartbeat and respiratory depression.
Haloperidol, an anti-psychotic drug, is used to treat psychotic disorders. If taken, it can cause, among other things, tremor, insomnia, agitation, excessive muscle activity and headaches.
Wong stated that he believed the unknown substance to be a "love potion".
"He claimed he had added the unknown substance in the hope that the victim would drink the contaminated water and fall in love with him," said APP Anitha, who sought the maximum fine.
In his mitigation plea, Wong's lawyer, Javern Sim, said his client has been diagnosed with "mood disorder" which caused him to be immature in thinking and to display attention-seeking behaviour.
"He was trying his best to get the attention of the lecturer that he liked very much," he added.
Mr Sim described Wong as a simple and caring man with a good character.
He was truly remorseful for his thoughtless and foolish actions, and had lost his job of 17 years as a result of them.
Wong could have been fined and jailed for up to three months.
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