HOW did this happen?
It is the question the family and friends of Maryborough shooting victim Karina Lock will struggle with for the rest of their lives.
But police are also puzzling over how her 57-year-old estranged husband Stephen Lock got hold of the weapon that killed her.
The mum-of-four was killed when Mr Lock shot her at a McDonald's restaurant in Helensvale on Thursday with an illegally-owned hand gun.
Mr Lock was the subject of a domestic violence order which was handed down in court two years ago, which meant he could not legally buy a firearm.
The order was due to expire in three months, when the shooting happened.
Detective Senior Sergeant Mark Procter said police were still investigating how Mr Lock got the gun.
Meanwhile, the couple's son Xaen Lock, 26, expressed his anger at those he felt had let his family down.
In a post on Facebook, Xaen blamed not his father for the tragedy but people he said "preach(ed) your doctrines of forgiveness but won't pray for another of Jehovah's children".
"Maybe if you ... minded your own business instead of sticking your noses where it didn't belong both would be alive today," he wrote.
He expressed love for both parents, describing his father as "his rock" and mourning his mother.
A man who once lived next door to the family said he had overheard yelling and shouting from their house at night, and he believed Mr Lock could be prone to angry outbursts.
The former neighbour, who asked not to be named, said he was aware that the relationship between the two was volatile.
"He was always going off in the middle of the night," he said.
Yesterday, the Granville home in Puller St, Granville where the family used to live was quiet. The family moved out after selling the home in February last year.
Then a few weeks ago, Ms Lock, 49, made the decision to move again, going from Maryborough to the Gold Coast in search of a new beginning.
She had agreed to meet her estranged husband in the car park of the McDonald's restaurant when he produced a hand gun.
Mr Lock followed his wife into the restaurant and shot her in the head before turning the gun on himself, in front of customers.
Ms Lock died almost instantly as a result of the severe head wound inflicted by her husband.
Stephen, who turned the gun on himself after shooting his wife, was taken to the Gold Coast University Hospital in a critical condition and died surrounded by his family yesterday morning.