Suspecting that her Singapore Civil Defence Force (SCDF) colleague had taken an upskirt video of her, a woman set up hidden cameras near her cubicle to catch him in the act.

As a result of the "sting" operation, Poh Siok Peng, then a major, was caught on March 9 last year. She made a police report the same day.

The 45-year-old married man pleaded guilty yesterday to two counts of insulting the modesty of the 26-year-old at the SCDF headquarters in Ubi Avenue 4 on March 4 and 9 last year. He will be sentenced on May 17.

On March 9 last year, Poh went to the victim's desk and chatted with her, the court heard. She then noticed him fidgeting with his mobile phone at her desk.

Footage extracted from the hidden cameras showed that Poh had used his cellphone to record a video of the victim from below her desk.

Deputy Public Prosecutor Chee Ee Ling said that some time in January and February last year, the victim noticed that Poh often came to her cubicle to chat with her.

"He would sit in front of her in an awkward position - constantly looking and bending down while chatting with her as though reaching out for something under her desk," she said.

Poh always sat in this position instead of standing by the victim's desk like other colleagues, especially when she was wearing a dress or skirt to work.

On one occasion, she saw a light flash from under her desk and realised he was taking upskirt photographs of her.

Although alarmed and distressed, she mustered up courage to inform the director of manpower on March 3, which resulted in the "sting'' operation.

DPP Chee said Poh had targeted the victim for two years before being caught. He had sold his previous mobile phones which he used to capture upskirt videos of the victim and could not remember exactly how many videos he had taken of her. He would view the upskirt videos in the wee hours of the night to relieve stress.

Seeking a sentence of at least six weeks per charge, DPP Chee said Poh had abused the victim's trust by repeatedly intruding into her privacy at her workplace, where she is entitled to feel safe and secure.

"It was entirely fortuitous that the victim had a habit of wearing safety pants," she added.

In his mitigation plea, Poh's lawyer Tan Hee Joek said his client, who has two children, had been working in telesales and administration since leaving the SCDF last May, earning $1,800 a month or about 20 per cent of his previous salary.

He said Poh was a victim of molestation in his teenage years and, as a result, experienced flashbacks whenever he was stressed.

He also said that Poh had served SCDF to the best of his abilities and is an active volunteer grassroots leader. He also does voluntary work at the Ang Mo Kio-Thye Hua Kwan Hospital and charity organisation Food from the Heart.

Poh's guilty plea, Mr Tan added, indicates his "deepest remorse and regret". He had sought professional help and is also receiving counselling.

The maximum penalty for insulting modesty is one year's jail and a fine.