As a trainee teacher, Yeo Chang Yong was supposed to protect and look after the secondary school students under his charge.
Instead, he abused his position and destroyed the "fundamental feeling of safety" by sexually abusing two of his former students, said Deputy Public Prosecutor Sharmila Sripathy-Shanaz in court yesterday.
Yeo, 30, had sex with one victim on six occasions after he had left the school. She was 15 and he was 26 when the offences were committed in late 2010.
He also committed a separate offence in the same year by fondling the breasts of the other victim, then 14.
Facing a total of nine charges, Yeo admitted to two counts of underage sex with the first victim, and committing an obscene act with the second.
DPP Sharmila told the court: "As a teacher, he had unbridled access to a pool of immature, naive and impressionable young girls. The evidence shows that he clearly had no qualms or reservations about taking advantage of the easy opportunity which presented itself to him, exploiting it fully to gratify his lust."
Yeo was posted to the victims' school as a contract teacher in 2009. He left the school in mid-2010 to complete his postgraduate diploma in education, and was giving maths tuition at the same time.
The first victim asked Yeo in 2010 to be her tutor and they began communicating with each other regularly.
On Sept 26 that year, they went on a date after tuition and ended up in a hotel room in Chinatown. They kissed when they were there but did not have sex.
In October and November that year, they had sex at Fragrance Hotel in Selegie Road and at Yeo's flat in Tampines.
She ended the relationship in 2012 and reported him to the police in September that year, after learning that Yeo had tried to woo one of her friends who was also studying at the school.
As for the other victim, the court heard that she also asked Yeo to be her maths tutor.
On Aug 7, 2010, Yeo asked her out for dinner and told her that he would tutor her afterwards. They met at Downtown East and he later took her to Pasir Ris Park, where he kissed her and fondled her breasts.
DPP Sharmila is seeking a jail sentence of at least 21 months for Yeo, saying his conduct was not due to a "momentary lapse of judgment" as he had intentionally planned to commit the offences.
Another aggravating factor, she added, was that he engaged in a sexual relationship with not one, but two minors.
Yeo returned to the school as a full-fledged teacher in June 2011 after obtaining his diploma. He is currently suspended from teaching.
District Judge Wong Choon Ning will sentence Yeo, who is represented by Mr S.S. Dhillon, on Feb 25.
Yeo faces up to 10 years' jail and/or a fine on each underage sex offence. For committing an obscene act with a young person, he could be fined up to $5,000 and/or jailed for up to two years.