S’pore man, 36, with diarrhoea fetish, tricked secondary school boy into taking laxatives, recorded video calls for 'research'

A 36-year-old Singaporean man, who has a fetish for watching teenage boys having diarrhoea and stomach cramps and had admitted to a series of offences against school boys, has been sentenced to six years and one month's jail.

According to CNA, Chew Jun Yang, Sean, faced a total of 28 charges, including cheating by personation, sexual communication for the purpose of obtaining sexual gratification, causing hurt by an unwholesome drug and deceiving a person into producing intimate recordings under false pretences.

He pleaded guilty to 11 of them, and the remaining were taken into consideration during sentencing.

At least 30 potential or actual victims

Between 2018 and 2023, Chew contacted at least 30 potential or actual victims, CNA reported.

He typically approached them over WhatsApp, claiming to be a former primary school classmate, and would ask them to guess his identity before assuming the identity of the schoolmate they named.

Chew would then request personal details from each boy, such as their name, age, school, and co-curricular activity, under the guise of conducting a survey for a school project.

Of all his victims, at least 19 of them provided some or all of the requested information to him.

At least 10 of them provided one or more personal photos to Chew at his request.

He also used the information to identify younger boys in Secondary 1 or 2 to target, and would ask for photographs as well.

He then told the victims he was working on an academic project and asked them to describe past experiences of food poisoning or diarrhoea.

He would also request voice or video recordings of the victims narrating or acting out their experiences, which he used for sexual gratification.

Would send substances to victims

According to CNA, in one case, Chew posed as a primary school friend of a secondary school boy and asked for his help with a project on how different bodies react to proteins.

Though the boy was informed that he would experience diarrhoea and vomiting, he agreed to take part, believing Chew to be his old friend.

Between January and July or August 2019, Chew sent the boy six packages containing substances such as cooking oil and baking soda, instructing him to consume them while on video calls.

According to CNA, Chew kept his camera turned off during those calls.

Whenever the boy had diarrhoea, he would send photos, answer questions and even act out his discomfort at Chew's request.

Chew recorded several of these calls, telling the boy the footage would be submitted to a research agency.

Some of these recordings exposed the boy's private parts, which made the boy uncomfortable, but Chew told him they would be censored before submission.

When the boy later asked to stop, Chew persuaded him to take part in one final session before letting him go.

He also asked the boy to write an essay about how he felt.

The deception came to light in January 2021, when the boy ran into the real friend Chew had been impersonating.

When confronted, Chew admitted what he had done and asked the boy not to report him.

Used victims to find new targets

Investigations found that Chew often asked existing victims to introduce him to other boys, CNA reported.

One such victim had agreed to take part in a supposed project on digestion involving the consumption of prune juice, but he felt no urge to defecate despite a lengthy video call.

Another boy, approached after Chew learnt he had once vomited in school after drinking bubble tea, refused to comply, finding Chew's request that he buy prune juice from the supermarket suspicious.

He was later shocked to learn from a teacher in August 2023 that Chew was not a fellow student, and proceeded to block and report Chew.

According to CNA, Chew was also found to have infiltrated an online chat group built around a mobile game by posing as a student, and later began talking to a Secondary 1 boy.

Continued offending while on bail

In April 2020, police seized Chew's phone in connection with earlier offences and found child abuse material involving two boys in school uniform.

Despite this, Chew continued to offend while on bail.

According to charge sheets seen by Mothership, in one case from around March 2023, he convinced a boy to take part in a fabricated "science statistical data challenge," requiring him to consume prune juice and provide photographic and video evidence of his bowel movements.

The boy went on to recruit friends to join the "experiment".

One of them subsequently experienced vomiting and diarrhoea in May 2023 after consuming substances given by Chew, which were later identified to have contained a laxative typically used to treat constipation.

Has a fetishistic disorder

A report from the Institute of Mental Health in July 2025 found that Chew has a fetishistic disorder involving hearing and watching videos of prepubescent males, around the ages of 12 to 15, experiencing diarrhoea and stomach cramps.

According to CNA, he was said to have had this condition since he was 17 to 18.

However, the report noted no link between the disorder and his offending, and found he understood the legal and moral implications of his actions at the time.

Disorder was "not mitigating"

Following Chew's arrest in September 2023, 19 recordings of a teenage boy, including him defecating, were found in his possession.

Prosecutors had sought a jail term of between six years and four months and seven years and one month, noting that Chew had previously served three years' jail in 2015 for similar offences.

They argued his disorder was not a mitigating factor, given his clear insight into his condition.