What a stolen motorbike reveals about a 47-year cold case

A 70-year-old man has admitted to riding one of three murdered friends' motorcycles just a day after they vanished, fresh details revealed this week in a reopened inquest into an outback Queensland cold case that has haunted investigators for nearly five decades.

Bruce John Preston testified at the two-week inquest into the October 1978 deaths of Karen Edwards, Tim Thomson, and Gordon Twaddle. The three had been travelling together on motorbikes, heading home to Melbourne for Christmas when they were last seen at Moondarra Caravan Park in Mount Isa. They were spotted in the company of a man driving a brown and white Toyota LandCruiser.

The trio's bodies were found decomposing in bushland near Spear Creek three weeks later. All three had been shot in the head. Their motorbikes, camping gear, and keys had vanished—a detail that would prove central to the investigation for decades to come.

For 47 years, Preston has remained a person of interest in the case. Cold-case detectives charged him with three counts of murder in 2019, but the Crown withdrew the circumstantial prosecution in 2023. Now, with Queensland coroner David O'Connell having reopened the inquest, fresh testimony is emerging that may yet clarify what happened that night.

At the heart of the inquiry lies a critical piece of evidence: Preston was found years after the murders in possession of Tim Thomson's red BMW motorcycle. He claimed he'd purchased it second-hand in Adelaide, but the receipt was forged, and he was convicted of stealing the bike. At the current inquest, Preston admitted he was riding Thomson's motorcycle on October 6—just 24 hours after the trio disappeared. He abandoned it only after his now-deceased father showed him a newspaper article about the murders and told him to "put the bike away." Preston said at that moment, "I got scared—up until then, I thought I was just guilty of stealing a motorcycle. All of a sudden, this is bigger than I could ever imagine."

The motorcycles' keys hold crucial significance. No keys were found at the murder scene, and the victims' pockets were empty. "It would be foolish to suggest that these gentlemen left their keys in their motorcycles," counsel assisting said. "Whoever had those keys must have gotten them from the victims' bodies."

Preston's father played an unexpected role in the narrative. He admitted his son had borrowed the family's LandCruiser—the same model seen at the caravan park during the hours of darkness on October 5. Before his death, Preston's father became convinced his son had committed the murders, the court was told.

Nearly 50 years on, the case remains unsolved. Preston was never convicted, and the three families have waited decades for answers. The reopened inquest offers hope, though the passage of time and loss of key witnesses present significant obstacles to closure.