SINGAPORE - A youth was just 14 years old when he committed sexual offences against an underage girl in July 2017.

From then until February 2020, the offender, who is now 18, went on to target nine more minors.

On Thursday (March 17), the Singaporean teenager was ordered to undergo reformative training - a rehabilitative sentencing option for young offenders - for at least a year.

This means that he will be detained in a centre and made to follow a strict regimen that includes foot drills and counselling.

On Feb 24, he pleaded guilty to four counts of sexual penetration of a minor below 16 years old. The charges involved four victims.

Another 29 charges, including those involving the other six girls, were taken into consideration during sentencing.

The offender cannot be named due to a gag order to protect the victims' identities.

The court heard that he met one of his victims in 2017 on Instagram. She was just 12 at the time.

She developed romantic feelings for him the following year and accepted his invitation to go to his home. Details about it have been redacted from court documents.

He took her to a staircase at his block of flats and requested to have sex with her.

The girl, who was then a virgin, agreed. Subsequently, they had sex at least once a month from June 2018 to January 2019.

In an unrelated case, he invited a 15-year-old girl to his flat to study after they got acquainted on Instagram in August 2019.

Deputy Public Prosecutor Ong Xin Jie had earlier told the court: "The accused informed her that his grandmother was home, but she did not notice anyone else present within the flat."

The youth then had unprotected sex with the minor. This girl's medical report later stated that she had felt sad, irritable and fearful since the incident.

The law finally caught up with the offender in June 2020 after one of the victims posted his photo on Twitter with the caption: "A rapist requested to follow me on Instagram, should I expose what he did to me?"

As a result, many other female victims reached out to her privately and shared their accounts of being sexually assaulted by him.

With their consent, their stories were shared on Twitter and gained traction.

The victims then lodged police reports between June and October 2020.

In an earlier proceeding, DPP Jane Lim told the court the youth not only exposed his victims to pregnancy and sexually transmitted diseases, the girls had also suffered psychological harm due to his actions .

DPP Lim added: "His offences are serious and would have attracted mandatory imprisonment if the accused was an adult."

For sexually penetrating a minor below 14, an offender can be jailed for up to 20 years and fined or caned.