His ex-partner, who did not want to be identified, said he used to be a corporal in the Australian Army.
He was from New Zealand but lived in Australia for several years.
"He served in some pretty nasty scenes - Rwanda, East Timor. He saw a lot atrocities," she said.
He left the army in the early '90s and had since displayed symptoms of post-traumatic stress disorder (PTSD).
"The reason that I've always suspected that he's had it has been the dreams. Combat dreams. He was diagnosed, finally, with PTSD about a year ago."
Just prior to the incident, he had signed paperwork regarding the custody of his two young children, a task he had found stressful.
"It just sort of pushed him over the edge, basically," the woman said.
"It was a cry for help I guess. I know that he was depressed earlier in the day and I guess it may have been that he regressed. He may not have been at (his address), he could have been elsewhere in his head."
She said the air rifle was not loaded.
Awaruku Rd resident Annie Sills said she came out to get her newspaper about 5.30pm when she saw a police officer across the road.
"He told me to get back inside because there's a man armed with a rifle.
"After that I heard a lot of 'pop, pops', which I presumed was an air rifle. He was just going berserk, it was over a dozen shots."
She heard police through a loudspeaker repeatedly saying: "this is the police armed offenders squad, we've got your house surrounded. Please come out by the front door. We're not here to hurt you".
"He must have started to open the door ... when he said 'I'm going to f****** kill you all'. We thought, this guy's unsettled in the head," Ms Sills said.
At one stage police lost sight of the man and set up a large cordon around the area as they feared he may have holed-up in nearby heavy bush.
Dianne Michels feared for her husband's safety because he was due arrive home during the seige.
"We didn't know whether he was in the house or whether he was running around. Our section is covered in trees, it would have been a perfect hiding place for him," she said.
"There was a lot of noise and there were obviously dogs, there was a lot of barking. I heard the dog handlers telling the dog it was a good boy but it must have been hurt because I could hear it yelping.
"The police were very good, I have to say, the whole operation was very well handled."
His flatmate fled to the next door neighbours' house, where they hid in the garage for three hours with the lights off and no toilet.
"I've known him for quite a while. He was just in a state of depression and mental illness," the flatmate said.
Police said the dog was receiving treatment.
