The Sydney Morning Herald said police sources were not authorised to speak publicly on the ongoing investigation.
A close friend of James told The Sydney Morning Herald: “She was always supporting everyone else’s dreams and goals. She worked really hard to better herself. She taught dance, she taught water polo.
“It showed she had huge care for the people around her, and for empowering the next generation of students. As a friend, she was always there to talk. Her light will always shine on.”
James had reportedly been dating her colleague Paul Thijssen in recent weeks, a 24-year-old sports coach at the school.
According to The Daily Telegraph, the pair had broken up a few days ago after dating for just over a month.
They state a fight is thought to have broken out between the pair at the school late on Wednesday evening, the topic of the fight is unclear.
Sydney police are currently undertaking a full-scale search for Thijssen in relation to the alleged murder.
In CCTV footage reportedly obtained by police, Thijssen and James are seen walking into the gym bathroom. Thijssen is then seen more than an hour later leaving the school.
Thijssen reportedly called police hours later to notify them of a body found at the school, according to news.com.au.
Sydney police were able to trace the phone call to an area in Vaucluse. A backpack and a number of belongings believed to be Thijssen’s were found.
DS Fileman said on Thursday morning they were investigating the possibility of whether Thijssen had committed suicide in the surrounding areas.
“We don’t want to make any assumptions of the fact that that person may have taken his own life, but that’s just another line of inquiry we’re looking at at the moment.”
News reports say that a team of investigators found an “item linked to the homicide” in the area.
DS Fileman says investigators believe there is no history of domestic violence between Thijssen and James.
One person who knew him well from the school told the Sydney Morning Herald: “There was nothing whatsoever to indicate any future trouble.”
Parents of students at St Andrew’s Cathedral School were told of the “critical incident” in a text from the school.
“St Andrew’s Cathedral School remains closed today to all students except those sitting Year 12 exams, as the school continues to work with Police following an onsite death overnight,” a spokesperson from the school said.
“No students were involved, and there is no ongoing threat.”
NSW Premier Chris Minns described the tragedy as a “horrible, horrible” crime. “One of the worst that I’ve seen in my public life.”