Tong Yau molested three girls and took naked pictures of one against her will. Chan Kiu-kei was re-employed within months of being convicted for taking lewd photos. Choi Hing-yiu took nude photos of his pupils. Lam Kam-wing was jailed for having oral sex with his students. Three were teachers; all but one worked in schools. Tong was a discipline supervisor at Madam Chan Wai Chow Memorial Primary School in North Point when he committed the offences. Convicted of indecent assault, he was jailed for 28 months in 2000. The school was accused of a cover-up because managers failed to take action after the victims' parents informed them about Tong's crimes, which only came to light after the parents went to the police. Maths teacher Chan caused a media storm this month when it emerged that he had gained a teaching position at Yu Chun Keung Memorial College No 2 in Pok Fu Lam after being convicted of taking lewd photos. Chan used a mobile phone to take 15 photos up a woman's miniskirt at Yau Ma Tei MTR Station in November 2008. He was sentenced to 220 hours of community service in May but was not removed from the teachers' register by the Education Bureau. Choi was a teacher at Heep Woh Primary School in Prince Edward Road, Kowloon, when he took nude photos of his students. At a court hearing last year, Choi admitted installing video camcorders under cartons in the school's music room. Police who examined the recorders found footage of students dancing and taking their clothes off. Choi, who was sacked when his crime was discovered, was placed on probation. Lam, a former primary school teacher, was convicted in 2000 of four counts of indecent assault involving oral sex with students at the tutorial centre where he worked. In January 2007 he was convicted of one count of attempted non-consensual buggery. Lam, who admitted the charge, was accused of impersonating a police officer to lure a Primary Four boy into a toilet in a shopping mall and attempting to sexually assault him. The judge said Lam had 'paedophile tendencies'.