Lilie James' killer used the hammer he used to kill her hours earlier to set up desks for his prestigious school's HSC exams, Daily Mail Australia can reveal.
The sinister new detail has emerged as police continue their investigation into the final hours of both Ms James and hockey coach Paul Thijssen.
And the school where Mrs James was tragically murdered now plans to create a permanent reminder of her short life in the form of a memorial or award in honor of her memory.
Daily Mail Australia has learned Thijssen was “at his best” on the day of Ms James' brutal death and was looking forward to coaching hockey the next day at the other school in the city where he worked, St Vincent's College.
His colleagues at that girls' school in Potts Point in central Sydney said they had noticed nothing wrong or different in his behaviour.
St Andrew's Cathedral School (SACS), where Lilie worked as a water polo coach, had asked Thijssen to set up desks in the gymnasium where the school's HSC students could take their exams.
Thijssen, 24, had a brief five-week relationship with Ms James before it was believed she had ended it.
Thijssen, a former SACS student, was commissioned to install desks and desks equipped with, among other things, a hammer from the school store.
The school's International Baccalaureate students had just started their final exams and the Year 12 students had started their HSC exams two weeks earlier.
Lilie is said to have met Thijssen that day sometime after 6 p.m. in the school gym.
Sinister new details have emerged about the day Lilie James, 21, (pictured) was murdered in the St Andrew's Cathedral School gym by hockey coach Paul Thijssen
Paul Thijssen, 24, (left) had been given a hammer to install desks for the HSC students taking their exams – possibly in the gym where he would later kill the water polo coach
NSW Police detectives were told The Daily Telegraph Thijssen was captured on CCTV buying a hammer at a hardware store that Wednesday morning, but they thought he had armed himself with two hammers.
Lily, 21, was found dead in the gymnasium bathroom later that evening.
The following day, St Andrew's closed its campus for two days but said the HSC exams would go ahead at another location, believed to be the Bishop Barry Center in nearby Druitt Street.
Police believe Thijssen beat Ms James to death with the hammer in the gym's bathroom before fleeing the scene.
The second hammer is said to have come from the school's storage room and is the alleged murder weapon.
The gym (pictured) where Thijssen was seen on CCTV following Mrs James into the bathroom before later emerging alone before driving to the Vaucluse and falling to his death
Mrs James is said to have agreed to meet Thijssen at the school later that day to return the sports equipment.
CCTV footage from the school allegedly shows Lilie and Thijssen entering the gym's bathroom, while Thijssen leaves more than an hour later.
About two hours after he allegedly beat Ms James to death, Thijssen was spotted on security cameras in the Vaucluse eight miles away.
Three weeks earlier, the young coach had been at the same location with Ms James, visiting one of her friends who lived on a suburban street in the Diamond Bay Reserve, overlooking the rocky stretch of coastline below.
He returned there after killing Lilie and was creepily caught on security cameras from Lilie's friend's house, which are pointed at the house's driveway.
The camera captured him arriving on the street in his rented white Lexus at 8:47 p.m. and then stopping at the end of the street.
The cameras then captured the Dutchman walking past the house at 9:04 p.m. trying to throw away the gun, eventually dumping the hammer he used to kill Lilie in a trash can.
Lilie James died on October 25 at the school where she worked as a water polo coach, just as HSC exams were being held for Year 12 students
Lilie James will be buried at her old school, Danebank, in a moving ceremony in which her father said his lively 'always on the go' daughter made him proud
Thijssen then returned to his car and sat there for two hours, calling Triple-0 just before midnight to report his crime.
After she was killed, he had already used Lilie's phone to send a text message to her father, posing as her, asking him to come pick her up from school.
Police traced the triple-0 call to The Gap, where they found an abandoned backpack with some of Thijssen's belongings, but no sign of him.
A daylong search in the Vaucluse on Thursday failed to find Thijssen, but a surprise discovery the next morning led police to believe he had thrown himself off the cliffs of the Diamond Bay Reserve.
Early on the Friday morning of October 27, tradesmen working on a boardwalk being built on the edge of the cliff above Diamond Bay spotted an object stuck in the rocks below and being pounded by waves.
It was Thijssen's body.
Police and rescue services attempted to retrieve the remains by jet ski and boat, eventually the body was recovered and carried down a path to road level.
Paul Thijssen, who left in 2018 with fellow former St. Andrew's classmate Matt, was optimistic the day he killed Lilie and then killed himself, coaching friends said
Paul Thijssen drives a white Lexus in the Vaucluse at 8.47 pm on Wednesday after leaving Lilie's body in the bathroom of the school gym
The remains were taken to a mortuary and later identified as belonging to Thijssen through medical records from the Netherlands, where he was born and lived before moving to Australia in 2015 and attending St Andrew's school for years 10-12.
Thijssen's parents, Esther and Stef, have reportedly made the decision not to repatriate their only son's remains back to Europe and Daily Mail Australia exclusively revealed that he had been cremated on November 8.
Thijssen's ashes were still in the Eastern Suburbs Memorial Gardens three weeks ago.
By contrast, friends and family gathered in brightly colored clothes to say goodbye to Lilie at her old school, Danebank, at a funeral where her father said in a statement how proud he was of his lively, always 'on-the-go' daughter.
Daily Mail Australia exclusively revealed last month that St Andrew's Cathedral School plans to demolish the gymnasium bathroom where Ms James was murdered.
It can be revealed that the school has indicated it will create a permanent memorial or award to honor Mrs James' life and work at the school.
Despite the tragedy that disrupted the school's HSC exams, SACS scored its best ever HSC results, finishing 84th in the state.
Principal Dr Julie McGonigle told Nine Newspapers that she had the highest praise for 'students who knew both Paul and Lilie well… had to pick themselves up and come back to do exams, and that's a very difficult situation'.
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