NSW Police have found a body in the sea below cliffs in Sydney’s east, in their search for a man missing after the discovery of a woman’s body at an exclusive private school.

Paramedics and police offers arrived at Diamond Bay just after 8am on Friday, as the search for Paul Thijssen resumed.

Part of the cliff was sectioned off as they searched the cliffs and coastline for any sign of Thijssen, who is wanted for questioning over the death of 21-year-old Lilie James at nearby St Andrew’s Cathedral School.

Police are yet to confirm if the body is related to the search for Thijssen.

James’ body was discovered with serious head injuries inside the gym toilets just before midnight on Wednesday. She was a water polo coach at the school, where Thijssen also worked.

Earlier, the ABC reported that 24-year-old Thijssen made the triple-0 call about James.

James’ family also contacted police when she failed to return to her Kogarah Bay home in Sydney’s south.

Superintendent Martin Fileman said on Thursday that officers found a “confronting” scene when they arrived at the school, due to the severity of her injuries.

Thijssen graduated from the school in 2017 and worked there as an assistant sports coach, according to his Linkedin profile.

On Thursday, police helicopters and boats patrolled the coastline off South Head. Fileman said detectives were investigating the possibility the man had taken his own life.

Thijssen and James knew each other but investigators were still working to establish the nature of their relationship, Fileman said. There are multiple reports they had been in a brief relationship.

An autopsy will establish the cause of James’ death.

Fileman said the circumstances of James’ death would also be confronting for students as it involved school staff.

“We’re currently working in with the school to ensure the welfare of the students and they have measures in place to make sure those students are taken care of,” he said.

NSW Premier Chris Minns offered his condolences to James’ family over the “horrible crime”.

“One of the worst I’ve seen in my public life,” he said.

“The St Andrew’s community, they’ve got a reputation of a very close-knit caring community, but they’re going to need to be in the weeks ahead.”

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Flowers were laid outside the school, which will be closed to students until next week except for those sitting year 12 exams.

St Andrew’s Cathedral in Sydney’s CBD held an evening service of prayers for school staff, students and families on Thursday.

“An area of the school, not accessible to students, is a crime zone, and we await the approval of police before bringing everyone back on site,” a school spokesperson said.

“The only students onsite are those sitting exams, and we ask that the media does not seek to interrupt their concentration or state of mind as they sit exams that are significant for their graduation.”

Police and the school did not believe there was any ongoing threat to students or the wider public after the attack.

School counsellors will be on site for parents and students as required.

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-with AAP