A delivery driver pretended to be a gym owner and threatened a 21-year-old student into paying him money after catching the student in the nude and being intimate with another man at the gym.

Tay Kay Hui, 23, also threatened to report the student to the police for trespassing into Segi Fitness gym in Middle Road on May 22 last year, causing the victim to pay him $1,000.

Yesterday, Tay was jailed for two months.

The sentence he received was similar to that meted out to his two co-accused.

Tay's accomplices, personal trainer Shaun Leow Qi Hui, 24, and Mr Leong Boyuan, 22, have since completed their jail terms.

Investigations showed that Mr Leow, who was working at Segi Fitness, had hatched a plan to lure people to have sex with him at his workplace.

When Mr Leow and the victim were undressed, one of his accomplices - Tay or Mr Leong - would film the victim in the nude and then demand money.

The court heard that the victim met Mr Leow on gay dating app Grindr and started chatting with him on March 21 last year. Mr Leow invited the victim to the gym for "fun" and to have a drink.

When the victim went to the gym later that evening, Mr Leow led him to a studio where they became intimate. But a few minutes later, the victim was shocked to see Mr Leong holding his mobile phone with the camera pointing at him. The victim immediately put his clothes on while Mr Leow pretended to be shocked and got dressed too.

Deputy Public Prosecutor Esther Tang said Mr Leong pretended to be angry and asked what they were doing at his gym. The victim apologised repeatedly. Tay and Mr Leong then scolded Mr Leow and the victim for tarnishing the reputation of the gym and threatened to call the police.

They demanded $5,000 from Mr Leow as "compensation" and he pretended to transfer the money via mobile banking.

Tay ordered the victim to pay the same amount.

Frightened by the threat of being reported to the police and that incriminating videos might be uploaded, the victim withdrew all the money he had in his account - $1,000 - from a nearby ATM and gave it to Tay through Mr Leow.

Mr Leow, Mr Leong, and Tay later went to a coffee shop to split the money. Each received about $330.

The victim reported the incident to the police on March 28.

Tay, who was allowed to start his sentence on Aug 21, could have been jailed for up to two years and/or fined for criminal intimidation.