Teacher, 28, caught grooming teen for sex on Grindr after girl, 15, posed as a boy on app to ‘entrap paedos’

A TEACHER has been found guilty of grooming a teenager for sex on Grindr after a girl posed as a boy on the dating app to help catch alleged paedophiles.

William Roberto Gulson, 28, was convicted of procuring a child under 16 for unlawful sexual activity after a three-day hearing in a Sydney court.

Gulson, a former Knox Grammar School teacher, began chatting in August 2024 with a profile run by two teenagers on the LGBTQ+ dating app Grindr, the court heard.

The girl, aged 15, was posing as a Year 9 boy “looking for older men”.

Despite being told the user was 15, Gulson allegedly carried on with a sexualised conversation for more than 40 minutes.

“Do you find it hot that you’re as old as some of my students?” he asked, before adding he felt conflicted.

After receiving a photo, Gulson replied: “Such a cute boy.”

The court was told he encouraged the teen to sneak out of his parents’ house so they could meet and find a “quiet place” for sexual activity.

He also allegedly described in graphic detail the sex acts he wanted to perform, 9News reported.

In court, Gulson denied believing he was speaking to a child, claiming he thought the account belonged to a “wacko adult” pretending to be young.

“I believed I was dealing with an adult male that was using the site,” he told the court.

He also claimed a search for “gay child porn” may have been auto-filed, saying he had no memory of typing it.

Magistrate Hugh Donnelly rejected those explanations, describing them as “wholly unconvincing”.

“His answers had the hallmark of recent invention,” the magistrate said.

The court heard Gulson’s internet history allegedly included searches such as “young boy raped movie scene” and “movies about priests molesting boys”.

“The former teacher had a sexual interest in children,” Donnelly said, adding: “Collectively, this is powerful evidence.”

Gulson reportedly showed no emotion as the guilty verdict was delivered.

He can now face up to 12 years in prison.

His bail was continued, meaning he is being allowed to stay released, until he returns to court for his sentencing in March.

Gulson did not speak to reporters as he left court alongside his brother.

The teenager’s family dialled into the courtroom to hear the outcome after being granted special permission.

Following Gulson’s arrest in 2024, Knox Grammar told parents the teacher had been immediately removed and his employment terminated.