An Arizona man has been arrested in the United States in connection with a shooting in rural Australia last year that left two police officers and a bystander dead, the F.B.I. and the police in the Australian state of Queensland said on Wednesday.
The arrest was announced at a joint news conference in Brisbane, Australia, by the two agencies. They did not release the man’s name, but a federal indictment that was made public in the United States later on Wednesday charged Donald Day Jr., 58, with two counts of making interstate threats, accusing him of making videos related to the shooting and posting them on YouTube.
At the news conference on Wednesday, an assistant commissioner of the Queensland Police Service, Cheryl Scanlon, described the shooting as a “religiously motivated terror attack” and said that Australian investigators had been working in the United States on the case.
The indictment said four police officers went to a remote property in the town of Wieambilla, in Queensland, on Dec. 12, 2022, to investigate a report of a missing person. The officers were fired on, it said, and two of them were killed.
According to the Australian authorities, a married couple who lived on the property, Gareth and Stacey Train, and Mr. Train’s brother Nathaniel Train killed the two officers, Matthew Arnold, 26, and Rachel McCrow, 29, as well as a neighbor, Alan Dare. The three Trains were killed in a shootout with the police.
The Trains subscribed to a “Christian fundamentalist belief system known as premillennialism” and saw police officers as “monsters and demons,” Deputy Commissioner Tracy Linford of the Queensland Police Service said earlier this year.
Ms. Scanlon said that Gareth Train began following Mr. Day on YouTube in 2020, and that the two commented on each other’s videos over the next year.
In 2021 and 2022, Mr. Day repeatedly sent messages containing what Ms. Scanlon described as “Christian end-of-days ideology” to Gareth Train and then later to Ms. Train. The couple also viewed videos from a YouTube account that Mr. Day created in 2014, she said.
The indictment said that between January 2022 and February 2023, Mr. Day’s online activity on YouTube demonstrated “a desire to incite violence and threaten a variety of groups and individuals, including law enforcement and government authorities.”
Using the name Geronimo’s Bones, he wrote in a comment on a video that the Trains had posted on YouTube after the shooting: “Please, do what you must do, with determination in your hand and fury in your bellies. Again, tell me that I can help you. Anything that is within my range to do for you, I will not hesitate.”
The U.S. attorney’s office in Arizona said that Mr. Day had posted a video on YouTube after the Queensland shooting threatening any law enforcement official who came to his residence. He also threatened to kill the director general of the World Health Organization in February 2023 on the video platform BitChute, calling on others to join him.
Each of the counts that Mr. Day faces carries a maximum sentence of five years in prison, a fine of up to $250,000 and up to three years of supervised release.
Nitiana Mann, a legal attaché at the United States Embassy in Canberra, said at the news conference in Brisbane that the suspect had made his first appearance in court in Arizona. It was not immediately clear if he had a lawyer.
Ms. Scanlon said that Australian investigators were continuing to work in the United States on the investigation.
“This is a terribly tragic event with a loss of lives,” she said. “We need to understand the ‘why.’”
