A spate of house break-ins was reported over a six-month period and the police were called in.
For months, they chased leads and interviewed victims and potential witnesses to end the criminal's crime spree.
When they finally identified him, it must have made them sick to their stomachs.
Because he was not just any other crook, he was one of their own.
Mohamed Faisal Mohamed Yusoff, 33, was a staff sergeant attached to the Divisional Intelligence Branch of the Central Police Division Headquarters.
Between August last year and February this year, he struck seven childcare centres, five residences, two kindergartens and even a church.
Yesterday, he was jailed five years after being convicted of five charges of housebreaking and theft by night.
Ten more similar charges were taken into consideration.
In all, he made away with about $30,000 worth of cash and goods, of which only about $4,100 had been recovered.
The New Paper asked the Singapore Police Force what type of information Mohamed Faisal was privy to and if he had used this to commit his crimes.
But the police did not respond by press time. According to court documents, the following are some of his misdeeds:
On Jan 10, he broke into Sunflower Tots and Kids Childcare at Frankel Avenue.
An administrative staff member who reported to work at 7.15am noticed the sliding door to the office had been forced open.
The previous night, Mohamed Faisal had climbed over the fencing and used a screwdriver to prise the windows open.
He ransacked the office, stealing a Nikon digital camera, one camcorder, seven crossed checks made out to "Tots and Toddles Pte Ltd" and $1,390 cash.
On Jan 26, he broke into a house on Mountbatten Road.
At about 9pm, he climbed over the concrete wall and entered through the unlocked main gate. He stole two laptops, an Apple iPad and its charger and $2,500 cash.
District Judge Kamala Ponnampalam said all of Mohamed Faisal's charges were serious, adding that each charge carried a minimum of two years' jail.
Mohamed Faisal pleaded guilty yesterday. It is believed he had been suspended since his arrest and will be sacked.
His parents, who were in court, declined to comment.
This article was first published in The New Paper.