Ryan Geoffrey Cole, 31, is accused of killing his neighbour, Natalie Frahm, as she sat in a car with two children in the driveway of her Mackay home in North Queensland, on June 19.

Cole was arrested by police after a manhunt across the regional city.

Police are investigating how Cole allegedly obtained the firearms after a weapons licence was revoked three years ago.

Detective Acting Superintendent Emma Novosel said investigators had recovered a homemade, inoperable long-arm rifle, an air rifle and a 22-calibre pistol.

She said preliminary forensic and ballistic advice led police to believe the pistol was the firearm allegedly used to kill Ms Frahm and seriously injure James McGill.

The 66-year-old Mr McGill was allegedly shot by Cole as he came to Ms Frahm’s aid after the two girls, aged 11 and 12, escaped the car.

He suffered hand and chest injuries as a result.

“None of the weapons located at that residence are currently, nor have they been previously, registered,” Supt Novosel said of the recovered firearms.

“Investigations are ongoing into the origin of the pistol and how it came to be in the possession of the defendant.”

Tributes have poured in for Ms Frahm, with a GoFundMe fundraiser also set up for the two girls.

The fundraiser had raised more than $23,000 by Monday.

In the wake of the Mackay shooting, the Queensland government called on MPs to back a bill that would allow warrantless searches by police for illegal weapons on “high-risk” individuals.

The bill was introduced in May and set to be debated later this year to address a 30 per cent rise in firearm-related offences in the past decade, with more than 3000 in 2023.

Cole has been remanded in custody after being charged with the murder of Ms Frahm and the attempted murder of Mr McGill.