A student visited a sex worker and threatened to alert the police about her activities if she did not hand over her money.
The 40-year-old Chinese national refused to comply and he left empty-handed.
Jonathan Kong Jia Xiong, a 19-year-old Institute of Technical Education student, pleaded guilty yesterday to one count of extortion.
On June 18, Kong received a phone call from someone known only as "Kelvin" who asked the Singaporean teenager if he wanted to earn "easy money".
Kelvin then told Kong that to do so, he had to visit the homes of various sex workers and threaten them that he would call the police if they did not give him cash. Kong agreed.
The next day, Kong went to the void deck of Block 236, Serangoon Avenue 3 at around 8pm to meet Kelvin, who handed him a mobile phone and some SIM cards.
Deputy Public Prosecutor Samuel Yap said: "He also gave the accused the phone numbers of the various prostitutes the accused was to visit."
Kelvin instructed Kong to contact the prostitutes using the SIM cards, with instructions on which card to use for the prostitutes that Kelvin had contacted, said DPP Yap.
About 30 minutes later, Kong went to the Hougang flat of one sex worker, who asked him for $100 upfront for her services.
DPP Yap told District Judge Eddy Tham: "The accused did not pay the victim, and instead asked the victim for money." When she refused, Kong told her that it was illegal to provide sexual services.
"The accused then attempted to put the victim in fear in order to commit extortion, by threatening to call the police to have the victim arrested for illegally providing sexual services in Singapore, unless the victim handed over her money..."
The court heard that Kong left the flat empty-handed when the woman refused to give in to his demand.
Yesterday, DPP Yap urged the court to call for a report to assess Kong's suitability for reformative training, stressing that the teenager had committed an "extremely serious" offence.
Those sentenced to reformative training must spend between 18 months and three years in a reformative training centre. They must also follow a strict regimen that includes foot drills and counselling.
Defence lawyer Peter Ezekiel asked the judge to call for a report to assess his client's suitability for probation. The lawyer also said Kong was a young offender who was not the mastermind of the scheme.
The Straits Times understands that Kelvin has not been dealt with in court. Court documents did not state if the authorities took action against the sex worker.
Kong is out on bail of $15,000 and will be back in court on Nov 27.