Police issued arrest warrants for 29-year-old Codye Thomson and 32-year-old Kaine Thomson-Gleeson, who allegedly assaulted and shot 23-year-old Mason dead on Railway Parade, Caboolture just after midnight on December 22.

Mason knew the pair and police said she had visited the Caboolture home where one of them lived.

Police said that Thomson and Thomson-Gleeson were questioned by police that day.

“There were a number of persons questioned on that day,” Detective Inspector David Harbison said.

“There was simply not enough evidence to suggest they were involved, hence they were released on that date.”

The brothers were spotted in Chinderah in northern NSW on December 30.

It is believed they then visited relatives in Kempsey on the Mid North Coast. 

“Our feeling is these two are probably sleeping rough or camping in that vehicle,” Harbison said.

Police did not seize the murder weapon on the morning of the attack, but have now revealed they later found a rifle at the crime scene, where tributes to Mason continue to grow.

Police want to speak to anyone who may have seen the brothers or their car, registered with Queensland plate 953 HO4.

“Obviously, these men have travelled some distance from Caboolture to across the border and would’ve interacted with members of the public along their journey,” Harbison said.

“I would appeal to anyone in northern NSW or even those in southern Queensland who believe they may have seen these men or this vehicle to come forward to police.

“Any little bit of information can go far in helping us in this investigation.”

Police have urged anyone who sees the pair not to approach them, but to call triple zero immediately.

Speaking with 9News, the woman’s family described her as the “most amazing person”.

“She’s someone that you would have wanted to have by your side in life,” her sister Dani said.

“She didn’t deserve this, no one does.”

Police are yet to establish the motive behind the attack or why she was with the two men on the street.