Why missing backpacker's mystery WhatsApp messages may never be revealed

The last messages of missing backpacker Theo Hayez may remain a mystery indefinitely, messaging giant WhatsApp has confirmed.

The 18-year-old Belgian native disappeared in Byron Bay 18 days ago and was last seen leaving the Cheeky Monkey’s bar around 11pm on May 31.

NSW Police admit they are "baffled" by the disappearance of the young man, who used encrypted messaging service WhatsApp the night he disappeared.

Belgian backpacker Theo Hayez was last seen on May 31. Source: GoFundMe

Theo’s father Laurent arrived in the country late last week and made a heartbreaking public plea on Monday for any information that could lead to his son’s whereabouts.

"Before I left Belgium I promised Theo's little brother Lucas that I would bring his brother home. Please, help me keep my promise to him," Mr Hayez told reporters through tears.

He also asked for help in obtaining access to Theo’s last messages.

Theo's last conversation could remain a mystery after WhatsApp confirmed that encrypted messages cannot be accessed. Source: GofundMe

"We understand the politics about confidentiality and respect that – however, this is a question of providing assistance to a person in grave danger," he said.

In a statement, WhatsApp said they were cooperating with NSW Police.

"WhatsApp cares deeply about the safety of our users and our hearts go out to Theo Hayez and his family,” a spokesperson said.

CCTV footage shows Theo at a bottleshop on the night he disappeared. Source: NSW Police

“We understand the important work being carried out by law enforcement and are assisting them in accordance with applicable law and our terms of service.”

The platform explains on their website that all messages sent and received via the app are encrypted.

“End-to-end encryption means that messages are encrypted to protect against WhatsApp and third parties from reading them.”

Laurent Hayez makes a tearful plea to the public for information on his son's whereabouts. Source: AAP

While WhatsApp can provide some details – including name, last seen date, IP address, email address, profile photo and other basic information – it cannot access the content of messages.

Public effort to help find Theo

Dozens of people, including State Emergency Service volunteers and members of the public, on Tuesday returned to the area around Cape Byron Lighthouse where the last 'ping' from Theo's phone was recorded on June 1.

He had been preparing to return home after eight months travelling Australia.

Homicide detectives are helping the investigation along with Belgian authorities but police hold hope Theo is still alive.

SES workers search cliffs in Byron Bay for Theo. Right: The hostel where Theo was staying before he vanished. Source: AAP

More than $65,000 has been raised via a GoFundMe page for the Hayez family, part of which was used to help Laurent Hayez fly to Australia.

Mr Hayez thanked police, volunteers and the community for their help in looking for his son, as well as those who raised money to support the search.

He said any crowdsourced funds not used to find Theo will be donated to a charity in Australia and Belgium dedicated to finding missing people.

Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or anonymously via https://nsw.crimestoppers.com.au.

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