Homicide police from Sydney have flown to Byron Bay to help find Theo Hayez.
The Belgian backpacker, 18, has been missing for 17 days since leaving Cheeky Monkey’s bar at about 11pm on May 31.
His father has arrived in Australia and is expected to give a statement on Monday.
Murder police from Sydney have flown to Byron Bay to help find Theo Hayez (pictured)
Mr Hayez was travelling on an eight-month gap year with his cousin Lisa Hayez and was due to return home a week after he vanished.
He was reported missing by staff from the WakeUp! Backpacker hostel after he failed to retrieve his passport and his belongings from his room.
His phone used WhatsApp in the early morning hours of June 1 – but has not been active since.
On Sunday Miss Hayez has posted an appeal on Facebook, asking if anyone knows who he last contacted.
She wrote: ‘Unfortunately it takes ages to WhatsApp to give any information to the police so if you could share this post so someone who knows someone who works for WhatsApp could help us to get these informations ASAP!’
Mr Hayez’s mother, Vinciane Delforge, told a French broadcaster in Belgium she is holding out hope her son is safe and well – but said his disappearance is entirely out of character.
‘We would love to believe that he met a girl and had a fling… and that’s why there’s no sign of life,’ Ms Delforge said.
The 18-year-old was looking forward to returning home to start his university course studying maths and science following and eight month trip around Australia
‘But that just isn’t him, that’s not his style.’
She said her son was a ‘meticulous planner’ who had thoroughly researched his gap year to Australia in the months prior to leaving his home town.
‘He is a conscientious, organised, responsible and attentive boy,’ she said.
Mr Hayez booked his flights and accommodation well in advance, mapping out his route across Australia and left little to chance.
His mother, Vinciane Delforge, told a French broadcaster in Belgium she is holding out hope her son is safe and well, but said his disappearance is entirely out of character
Locals have joined SES and surf lifesaver groups, police dogs, drones and officers from the Byron and Tweed stations to scour acres of swamp, beach and bushland for the missing teen.
Byron – known for its hippy, laidback lifestyle and celebrity appeal – is used to people floating in and out of the area but locals believe this case is different.
Long term Byron Bay resident Nicoletta Revis told The Age in her 20 years living in the area she had ‘never seen anything like this’.
‘This is totally different, this is totally next-level different and I haven’t experienced this before,’ she said.
‘People always show up in Byron.’
Dozens of locals have offered to support Mr Hayez’ devastated family who have been offered free food and accommodation.
CCTV footage shows Mr Hayez allegedly walking away from the Cheeky Monkey (pictured) and checking his phone just before midnight on May 31
The Byron landscape provides its own challenges in the search, with its dense, swamp-like bushland and waterways.
Beaches stretch for kilometres at a time and are often surrounded by long, marshy grass.
CCTV footage shows Mr Hayez walking away from Cheeky Monkey’s and checking his phone just before midnight on May 31.
He appeared to be heading towards the Wake Up! hostel north of town, where his passport and belongings were later found untouched.
Lisa Hayez said there is no way he would have wanted to disappear.
‘We’re sure like 100 per cent sure that his goal was to go back to the hostel to sleep,’ Ms Hayez said.
Mr Hayez (left, on night he disappeared, and right, with cousin) left his passport and belongings at his hostel
Mr Hayez’s godfather Jean-Phillipe Pector (left with Mr Hayez’s cousin Lisa) said it was completely out of character for the 18-year-old to not make contact with his family and friends
His godfather agreed, saying the teenager did not take drugs and would never have put himself in dangerous situations.
Byron Bay Command Superintendent Dave Roptell said police are ‘not ruling out anything at the moment’, and has urged anyone with information to come forward.
‘It’s baffling on two points from an investigation point of view, because we don’t know what’s happened – I feel for the family,’ Supt Roptell said.
Mr Hayez hasn’t made any financial transactions since he was last seen, prompting ‘grave concerns’ for his welfare, a NSW Police spokeswoman said.
A GoFundMe page set up to help Mr Hayez’ family come to Australia and assist in the search efforts has currently raised more than $60,000.
The traveller appeared to be heading towards the Wake Up! hostel (pictured) north of town, where his passport and belongings were later found untouched
Police previously released footage showing Mr Hayez walking from the Cheeky Monkey’s nightclub wearing a black hooded jumper, beige pants and black shoes.