A District Judge ticked off a man for not only betraying the trust of a teenage girl and her family, but also his wife, after he committed multiple sexual offences with the girl, then 13.

"You have no conscience,'' District Judge Lee Poh Choo told Muhammad Zhafir Ahmad, 27, before packing him off to prison for 30 months on Wednesday. The offences came to light in September last year when the victim's mother found pictures of her daughter and Zhafir kissing on her mobile phone.

Zhafir, a public servant, who faced 17 charges, pleaded guilty to five counts of sexually abusing the 13-year-old girl at her home and in his car between April and August last year. The other charges were taken into consideration.

A district court heard that Zhafir and his then-fiancee, whom he later married, knew the victim's mother. In September 2011, he invited the victim and her siblings to a movie but only the victim went. After this meeting, they contacted each other regularly over the phone and through text messages. The victim told Zhafir that she saw him as a boyfriend. He accepted her as his girlfriend just one day before he got married, said Assistant Public Prosecutor Raja Mohan.

In April last year, after an outing, Zhafir had consensual sex with the girl at her home and told her to keep it a secret.

The following month, he picked her up from school in his car and drove her to a multi-storey carpark in Jurong West where they were intimate again.

In the last proceeded charge, the pair were intimate in his car at a carpark in Dover Crescent in late August last year.