A tutor who asked to have sex with a nine-year-old student, molested three more and watched pornography involving one-year-old babies has been jailed for 4-1/2 years.
District Court Judge Johnny Chan Jong-herng said Cheng Wan-kwun, who pleaded guilty to 11 child-sex-related charges, was "a huge threat to children".
The court heard that Cheng, 29, molested the four girls aged eight and nine at a tutorial centre in To Kwa Wan, touching their thighs and hips on multiple occasions last year.
In a love letter to one of the girls, he wrote: "This week is my birthday. Even though you are only nine, I really love you. I really want to make love to you, so you can have a baby of ours! Can you grant me this birthday wish?"
He was arrested after the girl told her father.
Police found a laptop at his home containing 4,460 photos and 215 videos of child pornography involving victims as young as one and many younger than five.
"What kind of sick people would watch babies being assaulted?" the judge asked.
Cheng said he had downloaded child porn since 2007.
Psychological and psychiatric reports found Cheng had paedophile tendencies and a "medium" or "high" chance of reoffending. Cheng claimed the root of his problems was seeing his parents having sex aged one.
The court also heard that he "gently slapped" the hips of his victims not in secret but in front of two colleagues. The defence argued this proved he was not in control of his behaviour.
Chan rejected the argument and said Cheng could have helped himself, for example by staying away from children.
The court heard Cheng had been a tutor since 2008.
He admitted charges including indecent assault and possession of child porn.
Chan said the sentence reflected the seriousness of what he had done to his students, the large amount of pornography Cheng possessed and the young age of the children depicted.