"It is healthy to stop searching." Theo Hayez's mum on her son's disappearance.

Listen to this story being read by Gemma Bath, here.

Vinciane Delforge knows she has to stop searching for her son, Theo Hayez, in order to survive. 

The 18-year-old hasn't been seen since March 31, 2019, after he left a Byron Bay nightclub at 11pm and made his way towards the beach. 

Back home in Belgium, Vinciane has told 60 Minutes in her first public interview, "If you want to go on living, there is a time when you need to stop. There will always be sadness - till the very end of our lives. But it is maybe healthy to stop searching."

Watch: Theo's mum talks to Tara Brown. Post continues after video.

She does think, however, that perhaps she stopped searching too soon after being told by NSW Police that they were calling off the search six weeks after he went missing. They'd told her that they believed her son had fallen off the cliffs at Tallow Beach, and drowned. 

"I couldn't believe that he would have been alone, walking on this trail in the bush all by himself. But on the other hand this theory was probably the most acceptable, because it was the least horrible one," she reflected.

"[But] I think that the police stopped very fast and decided it was the theory of the accident that was the correct one, and today I see the police didn't explore additional possibilities," she said. 

It was Vinciane who first raised the alarm that her son was missing. She contacted Theo's Australian-based godfather, Jean-Philippe Pector, when she hadn't heard from him in five days. 

Together, they realised that Theo had never checked out of his Byron Bay hostel, and never hopped on the bus he'd booked to Sydney. The harbour city was supposed to be the last stop on his Australian holiday, before he headed home to start an engineering degree. 

"I really felt that, uh...my life would change forever," said Vinciane of that realisation. 

Theo was last seen captured on CCTV outside the Cheeky Monkey's nightclub on the evening of May 31, 2019.  

It'd already been a week when police started investigating, but they were further hindered by privacy laws that exist for missing person's cases that prevented them from accessing Theo's phone data. 

Once again, it was Vinciane who managed to crack that - she remembered Theo's Google password. 

But it meant that GPS tracking and Theo's final Google searches weren't accessed for 17 days after he was last seen, something Theo's family remains frustrated and shocked by.

The data gave incredible insight into Theo's last movements, showing that he paused for seven minutes at some cricket nets at the Byron Youth Activities Centre after leaving the Cheeky Monkey's nightclub, before heading in the opposite direction to his hostel towards the northern end of Tallow Beach, via a very off-the-beaten-track bushland trail. 

His phone movements stopped at around 1am the next morning beside the beach, but his phone stayed on and in the same general vicinity for the next 24 hours. 

READ: It's been three years since Theo Hayez went missing in Byron Bay. New leads are still coming in.

Theo's family, as well as Ken Gamble - the private investigator they hired to help them find him - do not believe that the teenager died by misadventure. Especially after seeing the phone data.

"I think that Theo had an encounter with maybe many persons, I also believe that he didn't feel the danger immediately but something has happened. But I know...I know he wasn't alone on that night," said Vinciane.

Ken agrees. Last week he told Mamamia's True Crime Conversations, "It would be an unusual circumstance where someone has fallen in the water to the extent that they had been washed away at sea, and their phone didn't go with them. Because if he's fallen in the water, the phone would have either been in his hand or his pocket."

"Based on all the evidence we've seen in this case, I don't accept the proposition that he fell off the cliffs. I don't believe the evidence shows that that's a logical conclusion," he added. 

60 Minutes host Tara Brown revisited Theo's last known location with former homicide detective Gary Jubelin to inspect the terrain. Jubelin also finds the theory that Hayez fell hard to comprehend. 

"I don't know about you, but I'm looking at those cliff faces and if you come off one of those cliffs you're not going straight in the water, you're hitting rocks," he told Tara. 

Vinciane said climbing those cliffs goes against everything she knows about her measured, sensible son. She'd even warned him of that very activity before he left for Australia.

Theo was nearing the end of his backpacking tour of Australia, when he went missing in Byron Bay. Image: Facebook. 

"I had warned him not to jump on rocks from cliffs, and to be careful not to fall into the sea. He told me he'd be extremely careful - that he would always calculate the risks. He would never jump off a cliff," she said. 

But the officer in charge of the case has said "nothing that has come to light during the investigation" to suggest there was some form of foul play or even homicide involved. 

On the ground in Byron, Jean-Philippe and his wife Julia spearheaded the family's search for answers. 

"We lived on adrenalin for weeks; trying to find out what could have happened...nothing could distract us, nothing else mattered," he told 60 Minutes.

"From the start we were 'we will find him.' I was driving at nighttime to see if he was roaming around, and seeing some young men that looked lilke him...the same smile....I would stop my car in the middle of the road and run towards them, and then a really thick Australian accent would come out of their mouth," he said.

Even now, years later, he's not giving up.

"We cannot give up. Whatever that answer would be, even if it's a horrible answer, it's better than not knowing."

This year, an inquest was held into Theo's disappearance, with the coroner due to hand down their findings within days. A $500,000 reward for information has also been announced in 2022. 

For Vinciane, there is a "still a tiny window open and because of that there is some hope," of finding some answers. But she can't focus too much on that. 

"I look to the future, and I move forward one step at a time. Day by day. I really need my life to have a purpose now, and I always need to do things that have a true meaning for me," she told 60 Minutes. 

She also hopes her family's story is a lesson to Australian authorities, in the hope that they become "better equipped to address those situations of missing persons." 

This will form part of the coroner's findings. 

For more on this case, listen to Ken Gamble's interview on True Crime Conversations. 

If you have any information about the whereabouts of Theo Hayez, please contact Crime Stoppers on 1800 333 000 

Feature image: 60 Minutes/Facebook.

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