A secondary school teacher lured three male students to his home and committed sexual acts on them, even giving cash to one of them for more than a year so that he would keep mum.
When a fourth student declined to visit his home, the teacher molested him in their school in the northern part of Singapore.
The teenager made a police report and the teacher's offences were uncovered.
The 36-year-old man, who has been diagnosed with paedophilia, was jailed for 6 ½ years yesterday.
He had pleaded guilty to five counts of performing oral sex on two minors and two counts of making one of them perform a similar act on him. He also admitted to one count each of molestation and sexually exploiting a child.
The Ministry of Education said the man left the teaching service on May 17 last year. He cannot be named because of a gag order to protect the victims' identities.
The accused was the first victim's teacher when the teenager was a Secondary 1 student in 2015. The court heard that the teenager was sent for detention on May 9, 2016, for circulating pornographic pictures in his class' WhatsApp group.
The man later spotted the 14-year-old boy in the detention room. Instead of advising the boy to behave himself, he asked the youngster whether he wanted to watch pornography with him.
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The accused asked (the boy) to go to his house and, in exchange, (the boy) asked the accused to pay him $50 so that he would not tell anyone that he had been invited to the accused's house to watch pornography together.
DEPUTY PUBLIC PROSECUTOR AMANDA HAN
Deputy Public Prosecutor Amanda Han said: "The accused asked (the boy) to go to his house and, in exchange, (the boy) asked the accused to pay him $50 so that he would not tell anyone that he had been invited to the accused's house to watch pornography together."
The man agreed and the boy went to his home the next day. The accused performed oral sex on him and continued to invite him home after this encounter, the court heard.
DPP Han said: "(The boy) would ask the accused to pay him his desired sum before agreeing to show up at the flat. This sum ranged from $50 to $300 and was not fixed, although it was usually around $100... This continued for almost 11/2 years."
The man approached his second victim in their school in July 2016. He asked the 13-year-old boy if he wanted to accompany him home to "play games". The boy agreed.
In his flat, the accused made the boy sit on his lap while they were playing a computer game and he thrust his body against the boy. The latter felt uncomfortable and left.
In July 2017, the man sent a text message to his third victim and invited the 15-year-old boy to his home without telling him why. The boy complied and they performed sexual acts on each other.
DPP Han said the accused asked his fourth victim to visit his home in August 2017, but the 13-year-old boy declined and the teacher later molested him in school.