Australian police officers have been given the green light to testify in the US trial of a man accused of links to the deadly Wieambilla shootings in rural Queensland.
The Queensland officers will be allowed to testify in an Arizona Court but will have to stick to "neutral factual" accounts of the incident.
A US federal judge will prohibit the officers giving more personal commentary that would lead the jury to "focus on the horror" of the shootings that claimed the lives of two police, an innocent bystander and all three suspects.
Brothers Nathaniel, 46, and Gareth Train, 47, used high-powered rifles during an ambush to kill Constables Matthew Arnold, 26, and Rachel McCrow, 29, at the remote Queensland property in December 2022.
Arizona man Donald Day Jr, 60, was charged a year later in the US with making threats to public figures and FBI agents, as well as with illegal firearms possession.
Day's lawyer Jon Sands early in March filed a motion to the US Federal District Court of Arizona seeking to prevent Queensland Police officers testifying at his client's upcoming trial.
"This approach ... provides all the context necessary for the government to prove its case, without requiring the emotionally charged testimony of Australian law enforcement officials."
US prosecutors had argued the jury needed to hear from the officers because Day shared beliefs with the Trains that police and government officials were "devils and demons" acting to enslave humanity.
The prosecutors said this evidence would support their claims that Day was serious when he allegedly threatened to kill FBI agents, public health officials and other high-profile people.
Judge John Tuchi on Monday, Arizona time, published a judgment allowing the Queensland officers to testify.
He found they could give evidence of Day's motive and intent when he allegedly made threats to kill in the days following the Wieambilla shooting.
"The court therefore will allow fact witness testimony as to why the constables came to be at the Trains' property that upon entering onto the property the Trains fired upon them, that the Trains killed two constables and a neighbour," Judge Tuchi stated.
The judge put restrictions on what the Queensland officers could say on the stand.
"The court will require neutral factual descriptions, but no characterisations — for example, witnesses may describe that Gareth or Stacey shot or killed a constable, but may not state that they ambushed or murdered the officer," Judge Tuchi stated.
"Such terms may be factually accurate, but they also are loaded, (and invite) the jury to focus on the horror of what the Trains did — for which (Day) is not responsible".
Nathaniel Train joined Gareth and his sibling's wife Stacey, 45, to fatally shoot neighbour Alan Dare, 58, soon after killing the two constables.
All three Trains were shot dead by specialist police officers hours later when they refused to negotiate or surrender.
Queensland officers will be able to testify about those events as well.
Queensland Police had proposed to send two police officers and three forensic officers to testify in the trial scheduled to begin on April 22 in Arizona.
