SINGAPORE - A police national serviceman who lost money in stocks and soccer betting stole three 100g gold bars worth a total of $13,800 from an 84-year-old retiree within a week, a district court heard.

Tan Bing Ren, 21, was a Special Constabulary sergeant when he committed theft from Madam Tjang Siang Le at her flat in Waterloo Street on Nov 24 and 30, 2015.

He was sentenced to 16 months' jail on Tuesday (March 14). Another charge of pawning a Credit Suisse gold bar for $4,600 was considered during his sentencing.

Investigations showed that Tan and his colleague went to Madam Tjang's home on Nov 24, 2015 to investigate a case of theft allegedly by Madam Tjang's domestic worker.

She ushered the police into her room and showed them the safe where she kept the money. The safe was secured by a number lock.

She took out most of the items that she had inside the safe and placed them on her bed. Among the items were jewellery which included four gold bars. One of the gold bars was placed near Tan's file.

Tan then formed the intention to steal the gold bar. He slipped the gold bar into the left pocket of his police pants when his colleague was engaged referring the case to the investigating officer and Madam Tjang was distracted, said Deputy Public Prosecutor Mansoor Amir.

Two days later, he sold the gold bar for $4,600 at Value Max Pawnshop at Buffalo Road.

He repaid his friend $2,000, a sum he had borrowed to settle a bank debt. Tan had lost $20,000 investing in stocks.

The next day, he called the victim's nephew to ask for her house number, saying he wanted to pay her a visit to find out how she was doing.

On Nov 29 that year, Tan called the victim to ask if he could visit her as he needed to discuss the installation of CCTV cameras in the unit with her.

"This was a ruse and the accused, in fact, wanted to visit the victim so that he could steal more gold bars," said the DPP.

Eventually, Tan went to Madam Tsang's home on Nov 30 after his night shift.

While chatting with her in the living room, he told her that he was "poor'' which was why he was working as a police officer.

After a while, he asked her to show him her valuables as he wanted to make sure everything was in order.

Madam Tsang led him to her room, opened the safe and laid out her valuables, which included three gold bars, on her bed. When she was distracted, he stole two of the gold bars.

The victim subsequently returned her valuables to the safe.

Later that day, she began to feel uneasy as she recalled her conversation with Tan. She checked her safe and found that three gold bars were missing. She then called the police.

Investigations showed that Tan had given one of the gold bars to his friend as repayment for a loan he had taken.

When his mother told him the next day that the police were looking for him, he handed the remaining gold bar to his girlfriend for safekeeping.

All the gold bars and the $2,000 have been recovered.

Tan, who was allowed to defer sentence until April 7, could have been jailed for up to seven years and fined on each charge.