Final Whatsapp messages of missing backpacker may never be read

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 in Australia 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.”

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.