To earn fast cash, three teenagers decided to rob sex workers here after one of them recalled watching crime television series Crimewatch which had a segment on a similar offence.

The court heard that Theophileous Jebaraj, 16, John Karan Karun-akaran, 18, and a 14-year-old boy were "inspired" to target sex workers as they felt that this was a "safer way of committing robbery". Court documents did not reveal details about the Crimewatch episode.

The older teenagers pleaded guilty yesterday to one count each of committing armed robbery. The young-est offender, who cannot be named because of his age, was convicted on May 15 but has not been sentenced.

Deputy Public Prosecutor Tay Jia En said Theophileous was sent to the Singapore Boys' Home on Oct 24, 2017 to serve an 18-month sentence for a separate offence, which was not stated in court documents.

He was allowed to temporarily leave the home on Sept 2 last year but failed to return.

While on the run the next day, he met up with the two other teenagers and they talked about their financial woes. John was on probation at the time for offences that were not specified in court documents.

The 14-year-old boy suggested stealing mobile phones but Theo-phileous rejected the idea as "the returns for stealing were little". Theo-phileous then recalled a segment in Crimewatch about robbery cases targeting sex workers and the trio decided to commit a similar offence.

After John conducted an online search, they decided to target two illegal sex workers from China who lived in a rented flat in Woodlands. They went to the flat at about 11.30pm on Sept 5 last year and a 36-year-old woman invited them in.

Her flatmate led Theophileous into a room where he whipped out a fruit knife, pointed it at her and demanded cash. After searching the room, he took from her $100 in cash.

He left the room soon after and told his accomplices to look for valuables. It is not known if they found any. The teenagers then fled the scene and the 36-year-old woman made a police report on Sept 9.

Yesterday, District Judge May Mesenas called for reports to assess if Theophileous and John were suitable for reformative training. Those sentenced to reformative training would be detained at a reformative training centre where they follow a strict regimen that includes foot drills and counselling.

The case has been adjourned to July 18.