A technician was brazen enough to commit crime right at the doorstep of the law enforcement headquarters by filming a woman employee using the toilet.

The victim turned out to be a police sergeant and on Wednesday, Ling Jia Hui, 24, was sentenced to a two-week short detention order and a nine-month day reporting order.

He had pleaded guilty last year to trespassing in a women's toilet in the Ministry of Home Affairs (MHA) building in New Phoenix Park and insulting the modesty of the 28-year-old victim by filming her relieving herself. He had committed these offences while he was doing cabling work at the building near Novena on June 6, 2012. A third charge of insulting the modesty of another woman by calling her on the phone and asking her for her breast size on May 7, 2012, was taken into consideration by District Judge Ng Peng Hong in passing sentence.

A diagnosis by the Institute of Mental Health indicated that Ling suffers from recurrent sexual fantasies, urges and behaviour, which involve non-consenting women. He had told psychiatrists there that he had the "urge" to take videos of unsuspecting women relieving themselves since November 2011 when he was deployed to MHA by his company. He also admitted to calling other women and telling them he had up-skirt pictures of them so as to humiliate them

Defence counsel Lim Kia Tong had argued for Ling to be placed on probation or sentenced to a mandatory treatment order but Judge Ng said that the offences were committed within the premises of a law enforcement agency so there was a need to send the right signal with a deterrent sentence.