Bruce John Preston 64-year-old is accused of the 1978 murders of Karen Edwards, 23, Timothy Thomson, 31, and Gordon Twaddle, 21, near Mount Isa in North Queensland.

Their bodies were found in scrub near Spear Creek, north of the mining town, less than a month after they set out on a cross-country adventure.

The trio had planned to ride from Alice Springs to Cairns and then Melbourne, to spend Christmas with family, but never made it.

They were last seen on October 5 jumping into a Toyota Landcruiser at Moondarra Caravan Park, in Mount Isa, similar to one Preston’s father allegedly owned at the time.

Their bodies were found 19 days later. All three died from gunshot wounds.

Preston, who denies the murders, was charged in April 2019 following a cold case investigation involving the Crime and Corruption Commission, the Brisbane Supreme Court heard on Friday.

The Crown case is the person who collected the trio from the caravan park is the murderer, but a recently released 1980 police report to the coroner describes that person as having a beard, Justice Peter Davis said.

“Preston does not in any way fit the description of the other person in the Toyota (with the victims),” he said, reading the report.

Further investigations found additional evidence corroborating that a bearded man was seen with Mr Thomson at other locations, he added.

Justice Davis said it appeared the investigating officers objecting to Preston’s previous bail application may have “overstated” some of the evidence against him.

He said the new information cast doubt on some aspects of the case, justifying bail.

Despite this, he said there was a prima facie case for Preston, a retired senior prison officer at NSW’s Goulburn Supermax jail, to answer.

Preston was allegedly seen with the three friends at two outback roadhouses and a Mount Isa hotel in the days before they were thought to have been murdered.

He was also found in possession of Mr Thomson’s near-new red and gold BMW motorcycle, which had a sidecar with a map of Australia painted on it, after he disappeared.

Preston, a former corporal in the Australian Army, told detectives he had found the bike and was convicted for stealing it.

He also told investigators in 1978 he was not in Mount Isa the day the trio were murdered.

But in an interview before his arrest in April, he contradicted this and said he was in Mount Isa when the trio disappeared.

Justice Davis noted that Preston was denied bail in June for fear he would take his own life after saying he would rather blow his head off than face prison.

However, a recent psychologist report found there was no indication he would self-harm.

Preston was granted bail and ordered to surrender his passport along with any firearms he owns.

He is expected to return to his family home in Goulburn, where he will be subject to a curfew and have to report to local police three times per week.