They were all teenagers when two friends allegedly held down a 13-year-old girl while Alson Tan Yu Seng, then 15, raped her in December 2013.
Describing the case as disturbing, District Judge Mathew Joseph sentenced Tan to a stint in the Reformative Training Centre (RTC) yesterday.
The judge said Tan, now 18, was fortunate that he was not tried as an adult.
The minimum sentence of eight years' jail would otherwise be imposed upon conviction.
Tan will spend between 18 months and three years in RTC.
His two co-accused will be dealt with later.
Tan, now a full-time national serviceman, admitted to one charge of rape that took place in his Bukit Panjang home.
He separately faced two charges of rioting in Cuscaden Road in March and June last year, which he admitted to.
Three other charges, including a second rape charge, were taken into consideration.
Tan's lawyer S. K. Kumar made a bid for him to spend Chinese New Year with his mother and younger brother.
But Deputy Public Prosecutor Sruthi Boppana objected, saying Tan had re-offended at other times while on bail and while police investigations were going on. The judge rejected Mr Kumar's application.
The girl's ordeal started some time at the end of 2013 after she met Tan and his friends, including alleged gang leader Koh Rong Guang, at an HDB block near Yew Tee Foodfare Food Court.
Koh, then 21, took her away from the rest of the group to a staircase, where he allegedly raped her.
Tan and one of his friends saw Koh performing what appeared to be a sexual act.
Koh, who told them to keep quiet about it, now faces four counts of rape.
On one night in December not long afterwards, the victim went looking for Tan Wei Guang, now 19, one of Tan's alleged accomplices.
He was at a basketball court in Bukit Panjang with Tan and another co-accused, Bryan Ong Jing Chong, 18.
The victim had developed feelings for Tan Wei Guang, whom she became acquainted with through Facebook, the court heard earlier.
The four then went to Tan's flat, where she was raped.
The judge said it was Tan who suggested to his friends to take advantage of her and it was he who brought up the perverse actions.
The maximum penalty for raping a girl below 14 is 20 years' jail and at least eight strokes of the cane. For rioting, the maximum punishment is seven years' jail and caning.
This article was first published on Jan 26, 2017.
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