The conduct of a teacher who had underage sex with one of his students and exploited another was "nothing short of deplorable".
In sentencing Yeo Chang Yong on Tuesday to 26 months in jail for the offences, District Judge Wong Choon Ning said Yeo, 30, had broken a sacred trust.
"You are, what one may call, every parent's nightmare. You supervise and monitor our children closely as we are aware of the possible dangers that they may come across in their daily lives, given their immaturity and naivety. There was deliberate and systematic sexual exploitation of the two minors under your care."
Yeo, who faced nine charges, had pleaded guilty to two charges of having sex with a 15-year-old student at a hotel and his home in Tampines in 2010. He had also admitted to fondling the breasts of a 14-year-old student at Pasir Ris Park.
While Judge Wong took into account Yeo's clean record and his plea of guilt, she added: "However, the sentences to be meted out must reflect the gravity of the offences, and the revulsion which this court, and I believe, the general community feel towards such conduct by the accused. The sentence must also be appropriately stiff to deter other potential like-minded offenders."
The court heard that Yeo was posted as a contract teacher to the two victims' school in 2009 and went back to the National Institute of Education to complete his postgraduate diploma the following year when the offences occurred.
When the first minor, then in Secondary 3, learnt that Yeo was giving maths tuition in 2010, she joined his classes.
They met at a McDonald's outlet in August that year and began to communicate regularly via text messages.
After one lesson, he dated her and they ended up resting in a hotel room although they did not have sex then. Their fist sexual encounter was at Fragrance Hotel in Selegie Road in October 2010. They had sex again at his home when he was on sick leave the following month.
In the case of the other minor, Yeo was teaching her computer applications in 2009. The following year she asked him to tutor her in maths and they did so over "Skype".
On Aug 7, 2010, he brought her to Pasir Ris Park and fondled her breasts there.
The offences came to light when the first minor lodged a police report in September 2012 after learning that while Yeo was still dating her, he had tried to woo one of her friends.
Yeo, who has been suspended, could have been jailed for up to 10 years and/or fined for each sex offence. For committing an obscene act with a young person, he could have been fined up to $5,000 and/or jailed for up to two years.