SINGAPORE - A Singapore Armed Forces (SAF) regular who had sex with a 13-year-old girl has been jailed for 15 months, after her parents arrived home to find him at their flat.

Tan Yong Jin, 24, and the minor had already dressed when her mother and father found them.

The teenager, who cannot be named, later admitted to having taken part in sexual activities with him, and her mother alerted the police.

The SAF sergeant was sentenced on Thursday (Jan 11) after pleading guilty two counts of performing consensual sexual acts with the child, who was a Secondary 2 student at the time.

Tan got to know the girl through Facebook in November 2016 and they became friends.

Deputy Public Prosecutor Amanda Chong said he was aware that she was under 14.

The pair stayed in contact after meeting for lunch later that month and began to exchange sexually-charged messages.

At around 11am on Jan 8 last year, the girl asked Tan to meet her at Clementi Mall.

Two hours later they went to a nearby cinema. When the movie ended at around 3.30pm, the pair took a bus to the girl's home in Jurong to have sex, as her parents were out.

DPP Chong said: "They were not in a boyfriend-girlfriend relationship. Upon reaching her residence, the victim made a check to confirm her parents were not at home, before leading the accused up to her residence. Inside her residence, she led the accused into her parents' bedroom."

Tan then had unprotected sexual intercourse with the girl and she performed oral sex on him.

Her parents came home after the pair had got dressed and saw Tan inside the flat. The girl admitted to them what she had done and her mother called the police. Officers turned up to arrest him.

District Judge Wong Li Tein said that Tan "should have known better".

For each count of sexually penetrating the minor, Tan could have been jailed for up to 20 years and fined or caned.