Whether missing Belgian backpacker Theo Hayez died in a tragic accident or met with foul play remains a mystery.
"There is simply insufficient evidence before me to substantiate or exclude either theory at this point in time," NSW State Coroner Teresa O'Sullivan said on Friday.
Delivering her inquest findings, she found the 18-year-old was dead but was unable to determine the cause or manner of his death.
She found he likely died on or shortly after June 1, 2019, at Byron Bay.
Excluding the possibility of suicide, the coroner also said there was no reason for him to intentionally vanish.
"The evidence presents a picture of Theo as a young man who was universally loved and had a bright future ahead of him."
Police have theorised Theo clambered up the beachside cliffs, dropped his phone then fell and was swept out to sea, something his family says goes against the teen's sensible, risk-averse nature.
They found it inconceivable that he would walk alone through dense unknown bushland in the middle of the night and do something as dangerous as climbing up a cliff face.
Instead, they suspect he met foul play after meeting a person or persons who guided him to the beach, caused his death and disposed of his body.
Theo was reportedly last seen about 11pm on May 31 when he was ejected from the Cheeky Monkeys bar after being deemed to be "approaching intoxication".
The coroner found no basis to criticise the decision, noting the bar's liquor licensing obligations and its policy of erring on the side of caution.
Police were alerted to his disappearance six days later, when he failed to return to his hostel and couldn't be found or contacted.
"A large-scale missing persons investigation was conducted by the NSW Police with ongoing and invaluable support provided by Theo's family, the local community in Byron, and the Belgian authorities," the coroner said.
Despite extensive land and sea searches, the only trace of Theo found was his grey Puma cap in Arakwal National Park, behind Tallow Beach.
Evidence placed the teen on a steep headland below the town's famous lighthouse around midnight.
Theo was tracked, using data gleaned from Google location services and his mobile phone connections, to a local sporting field after being ejected from the bar.
He then charted a route through the national park to the beach below the headland, before the data shows his phone climbing the steep ascent towards the lighthouse.
The last GPS data places his phone near the cliffs at 12.05am.
"There is user activity on Theo's phone for approximately an hour after this point, until 12.56am, showing him accessing YouTube and exchanging messages with friends and family," the coroner said.
While she found that Theo's cautious character was inconsistent with him taking the very dark and obviously dangerous pathway alone, she also noted his online activity between midnight and 12.56am.
This included watching a clip of a comedy show and sending light-hearted messages which was inconsistent with him feeling afraid or in any kind of danger.
Police in February announced a $500,000 reward for anyone with significant information about Theo's case.
"It can only be hoped that this reward will provide an incentive to persons who may have important information but who have so far been reluctant to come forward, to contact the police and help solve the terrible mystery of what happened to Theo on that night."
She concluded by making recommendations to cut the red tape involved in searching for missing persons.
This included considering introducing or expanding powers relating to CCTV footage and to obtaining information from technology such as smart phones and computers.
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