Disappearance of Théo Hayez

Théo Hayez was an 18-year-old Belgian man travelling in Australia on a working holiday visa, having arrived in late 2018. He disappeared roughly a week before he was scheduled to fly home to Belgium. He was last seen leaving Cheeky Monkey's bar in Byron Bay, New South Wales, at approximately 11:00 pm on 31 May 2019, in the Cape Byron area.

Hayez had been staying at the Wake Up! hostel in Byron Bay. Staff there contacted police on 6 June 2019, three days after he failed to check out, and his family — concerned by his lack of contact and his failure to return to his accommodation — also called New South Wales police that same day. Hayez's personal belongings, including his passport, remained in his hostel room.

Australian police mounted a substantial search effort, employing helicopters, drones, cadaver dogs, trackers, divers, and rock climbers. Hayez's parents, Laurent Hayez and Vinciane Delforge, travelled from Belgium to Australia in June 2019 to take part in and support the searches. His father publicly appealed to the Australian public for help, invoking a promise made to Théo's younger brother, Lucas, that he would bring Théo home.

Investigators determined that Hayez's final phone signal placed him in the vicinity of Cape Byron on 1 June 2019. Further analysis conducted with the Hayez family and Google pointed to a possible last known location near Cosy Corner at Tallow Beach. The messaging platform WhatsApp cooperated with New South Wales Police in an effort to retrieve chat logs from that night, though the encryption of the service limited what could be recovered.

The Hayez family continued to press authorities to pursue leads in the case. In July 2019, community search volunteers responding to the family's appeals found a grey Puma hat similar to the one Hayez had been wearing on the night he disappeared, in bushland at Tallow Beach.

As the investigation slowed, police developed a working theory that Hayez may have fallen from cliffs near the Cape Byron lighthouse in an incident of "misadventure." Multiple possible explanations were considered for why he might have been in that area after midnight, including being lost, being misdirected by a mapping application, being under the influence of alcohol or drugs, being suicidal, having been led there by a local person, heading to a party, or having been hurt or attacked. Possible explanations offered for the absence of a body included human intervention, being lost in the bush, being taken by a shark, or being swept away by tides. A coroner's inquest into the disappearance was scheduled for November 2021.

The case attracted significant media attention in both Australia and Europe. At the request of Hayez's family, an Australian national crime correspondent joined the search efforts and later documented the case in a six-part podcast released in late 2019.