A coroner has found there is not enough evidence to definitively say Maddison French - who vanished while exploring Australia in 1997 - was killed by serial conman and identity thief Miro Dragovich.
Despite yesterday's finding, Mr French's mother Margaret is in no doubt.
Mr French last contacted his family on December 17, 1997, from a phone box in Carnarvon when he told his girlfriend he intended to travel around Australia with a friend, Marco.
Marco was in fact Miro Petrovich Dragovich, a refugee with more than 20 aliases who was already wanted by police and who was later jailed over an international money scam.
Mr French's disappearance became a murder investigation after it emerged Dragovich had used his identification to book into hostels and his bank account was accessed all over Australia - but not while Dragovich was out of the country.
It then emerged that Dragovich had used false passports to flee abroad, had been arrested and jailed in New Zealand and then extradited to Australia where he changed his name again after his release from jail.
After an inquest into the death of the 24-year-old, State Coroner Ros Fogliani returned an open finding, saying she could not rule out natural causes or an accident.
She also noted Dragovich must have been aware of Mr French's death when he attempted to cash in his disability pension on November 10, 1998, and that Mr French's last days were "inextricably connected" with Dragovich.
Despite a $100,000 reward and many public pleas, Dragovich was never charged over Mr French's death.
He killed himself in 2003, taking any knowledge of the disappearance with him.
Speaking from her Duncraig home, Mrs French said despite the open finding, and lack of closure, she was certain he was responsible for her son's death.
"There is no doubt in my mind," she said. "He was such a smooth operator and Maddison had no idea about his past. That man got away with it."
Last year, Mrs French and her daughter Fiona retraced the last known movements of Mr French, including standing at the spot he made his last call.
"That was very emotional but there is no closure, there is never closure," Mrs French said.
"It is such a huge expanse out there. He could be anywhere and we will never know exactly where."