After more than 20 years, a botched police investigation and three coronial inquests, a Queensland man has been committed to face trial over the shooting deaths of his wife and her best friend.
For more than two decades it was thought the women died in a murder-suicide pact.
But in a sensational finding on Friday, State Coroner Michael Barnes committed Mrs Leahy's husband Alan to stand trial for unlawfully killing both women.
He ordered a warrant be issued for Mr Leahy's arrest.
But the final decision over whether an actual trial will take place will rest with the Director of Public Prosecutions (DPP), who needs to ensure there are reasonable prospects of a conviction.
The limited availability of witnesses, the loss of important physical exhibits and the fading of witnesses' memories could all work against prosecutors, Mr Barnes said.
However, he rejected the long-held belief and previous ruling that Ms Arnold, 27, had shot and killed her 26-year-old friend before turning the gun on herself.
Mr Barnes said the evidence indicated the gun, which was found by Ms Arnold's hand, was planted.
The shooter would have had to have been a third person firing from the back seat.
The coroner also suggested there were key pieces of circumstantial evidence against Mr Leahy.
He had motives, was the last person to see the women alive and lied about many indisputable facts following their disappearance.
Mr Barnes said Mr Leahy, who was in financial trouble, stood to gain $120,000 from his wife's life insurance policy.
He was also in a sexual relationship with her younger sister.
Mr Leahy also owned "true crime" magazines that described an incident where a killer had manipulated a multiple murder scene to make it look like a murder-suicide.
Mr Barnes was highly critical of the botched initial police investigation that supported the murder-suicide theory.
"This sad and confronting case has confounded numerous previous inquiries," he told the court.
"Mistakes made by police when the women first went missing, through the initial scene examination and in the days following the discovery of the women's bodies, made more difficult what was always going to be a complex case."
Mr Barnes said detectives didn't recover lost or corrupted evidence that could have helped solve the crime during the initial investigation.
"They then set about squeezing whatever evidence was left into an explanation that required no further action to avoid having to confront the potential prosecution that had been compromised," he said.
Emotional members of the women's families broke down when Mr Barnes announced his finding.
Outside court, Ms Leahy's younger brother, Peter Martin, said his family had waited 20 years for the finding arrived at by Mr Barnes.
"I'm on top of the world," Mr Martin told reporters.
"It takes Vicki straight out of the picture, as it should have been from the word go.
"We knew the story. We did the homework. We had to do their (police's) job.
"If they didn't baffle it up the first time, we wouldn't be here today."
Mr Martin said he would celebrate with "a few beers".
Mr Barnes was able to commit Mr Leahy to stand trial under legislation covering inquests that are heard for cases that arose before 2003.
Queensland police says for operational reasons they won't reveal if officers know where Mr Leahy is.
But once an arrest is made they will announce it.
"The service is currently processing the arrest warrant issued by the Coroner for Alan Leahy for the offence of murder," police said in a statement.
In response to his criticisms of the way the case was handled in the past, the police service said it recognised the coroner can introduce and assess information that isn't always available to investigators.
"He can also consider that information as part of his findings," its statement said.
"The Service remains in a position to assist the Director of Public Prosecutions should this be requested."