An accountant was jailed for four years yesterday for taking photos up the skirts of dozens of women using a mobile phone that had an application allowing him to avoid detection. Lam Sai-ho, 28, had earlier pleaded guilty in Eastern Court to 20 counts of behaving in a disorderly manner in a public place. He was caught after he took photos up the skirt of a woman at Admiralty MTR station on July 9. Police found on his phone 201 images of 36 women taken between June 28 and July 9. Magistrate David Dufton noted that Lam had downloaded the software. "Reports reveal that the defendant had downloaded an app which allowed him to take photos without detection, which shows a degree of premeditation," he said. Dufton did not say what app it was or what features it had that enabled Lam to avoid detection. A crop of cellphone apps with "spy camera" features has appeared on the market in recent years. One item of software selling in an online app store programs the phone to show an unrelated image on its screen when the user takes a photo. Pictures are snapped by swiping a finger across the screen or pressing the volume buttons. Another app does away with the use of a flash or the click of a shutter. The image taken does not show up either; instead, a black screen appears. Lam was found out after a passer-by noticed him riding an escalator with one leg on the step above and a mobile phone balanced near the knee of that leg, angled towards a woman in front of him. The man was not sure whether Lam was taking photos, but later called the police. Police found on Lam's phone 24 photos up the skirt of the woman taken without her knowledge. Defence lawyer Shum Ka-hei said his client was working at one of the four big audit firms at the time and was under stress.