Paul Thijssen called police and notified them of Lilie James’ body at St Andrew’s Cathedral School

The ex-boyfriend of a young water polo coach found beaten to death at one of Sydney’s top high schools rang triple-0 himself and told them where to find her, four hours after police believe she was killed.

The ex-boyfriend of a young water polo coach found beaten to death at one of Sydney’s top high schools rang triple-0 himself and told them where to find her, four hours after police believe she was killed.

Paul Thijssen, 24, could be seen on CCTV following Lilie James, 21, into a gym bathroom at St Andrew’s Cathedral School about 7pm on Wednesday.

The Daily Telegraph understands Ms James had brought their relationship to an end in recent days, after five weeks together.

That same CCTV camera sees captures Thijssen leaving the area well over an hour later, while Ms James never comes out of the bathroom.

Close to four hours later, not long before midnight, Thijssen – a Dutch-national who worked alongside Ms James in the school’s sports department – rang police to inform them there was a body at the school they should investigate.

Paul Thijssen followed Lilie James into a gym bathroom. He later emerged, she never did.

Uniform officers soon arrived at the Kent St school where they found Ms James suffering horrific injuries.

It is not known if Thijssen made admissions during his triple-0 call about involvement in her death, but a trace of his phone led officers to notorious Vaucluse suicide spot “The Gap” where they found a backpack and some of his belongings.

NSW Police Superintendent Martin Fileman said property related to the “actual homicide” had been found at Vaucluse, but he would not clarify if a weapon had been seized.

Property related to the “actual homicide” had been found at Vaucluse. Picture: NCA NewsWire / Jeremy Piper

“Police located the body of a female in her early twenties in the gym area of the school,” he said.

“It is apparent from her injuries she’s a victim of homicide. She had serious head injuries. The actual scene itself was quite confronting for the police who turned up.”

Supt Fileman also confirmed other staff were present at the school at the time the body was discovered.

“We’re currently speaking with a number of witnesses,” he said.

Officers found Ms James deceased in the bathroom with horrific head injuries. Picture: NCA NewsWire / David Swift

“We believe he was employed also by the school … they are known to each other.”

A PolAir helicopter searched along the cliffs at Diamond Bay for much of Thursday morning without any sight of Thijssen.

Thijssen had moved to Sydney from the Netherlands in 2015, starting at the elite school.

There he had excelled, quickly becoming an integral part of the school community, including as a captain of sports teams in his final year, 2017.

According to his LinkedIn account he remained in Sydney for two years after graduating, during which time he worked at St Andrews as an assistant in the sports department.

He then returned to the Netherlands for 12 months, before flying back to Australia.

For the past three years he had worked at St Andrew’s Cathedral School, as also picking up a position at St Vincent’s School in Potts Point.

Thijssen was a sports captain at the school in 2017.

He initially moved to Australia from the Netherlands in 2015.

In recent times he had struck up a relationship with Ms James, a vibrant young water polo player who had grown up in Sydney’s southeast, before following in her father Jamie’s footsteps to become a coach in the sport at St Andrew’s Cathedral School.

Parents who arrived at the school to drop off their children early on Thursday unaware of what unfolded overnight were shocked to be told what had happened.

“There’s an incident that’s occurred. The school is closed,” a police officer told a father-of-two standing behind police tape.

St Andrew’s has closed its doors for the rest of the week, although HSC exams and a junior school camp will still go ahead.

A makeshift memorial was set up at the entrance to the school, with bouquets of flowers left by mourners.

Lilie James had just called off her brief relationship with Thijssen.

She’s been remembered as the “nicest and kindest person”.

A parent of a current student at the school paid tribute to Ms James, saying she was “the nicest and kindest person”.

“They all loved her … my daughter and her friends are so upset,” the parent wrote on social media.

In a letter to St Andrew’s parents, Head of School Dr Julie McGonigle said counselling had been made available to any student who required it.

“I understand that this is a highly upsetting and concerning update, and I want to reiterate my support for our entire school community,” Dr McGonigle said.

NSW Police have launched Strike Force Trineura to investigate the incident, and are continuing to search for Thijssen.

“We ask everybody to be mindful we have numerous students turning up today for school and the HSC,” Superintendent Fileman said.

“They’re going to be confronted by this today.

“As you can imagine it’s an extremely sad time for everybody.”

Originally published as Paul Thijssen called police and notified them of Lilie James’ body at St Andrew’s Cathedral School