Alpha Cheng was holidaying in South Australia when he heard the news about a shooting outside the NSW state police headquarters, in Parramatta.
"I didn't think too much of it," he tells Insight's Jenny Brockie. "But shortly after, my sister called. The police had called her to say that the victim outside the New South Wales Headquarters was Dad."
"A 15-year-old assailant had walked up behind him and shot him in the back of the head."
It is something Mr Cheng is still processing, but hopes certain changes can be made to make the country safer.
Speaking on Insight's episode on , Mr Cheng says he is concerned about the accessibility of firearms to criminals, in particular, and questions whether the gun control laws brought in 20 years ago are still doing enough.
He sought the advice of the architect of those laws, former Prime Minister John Howard.
"My question for Mr Howard is: are our gun laws adequate in protecting us? Are we as safe we think we are?" Mr Cheng asked.
"What do we need to do make our society safer? Do we need another amnesty to remove guns and weapons from society."
Mr Howard replied that the gun laws were "almost certainly" inadequate.
"I would have thought that everyone will agree, if 15-year-olds can get hold of weapons like that, there is something wrong with the laws," he said.
For Mr Cheng, the age of the attacker was particularly pertinent.
"I'm a high school teacher that works actively with teenagers, and it completely baffles me how we are allowing, that it is possible to access a gun at such a young age," he says.
Mr Howard also said that he "would not object at all" to another amnesty, particularly at the federal level, but has not been actively campaigning for one.
While he has not discussed this with current Prime Minister Malcolm Turnbull, if asked, Mr Howard would "say the same thing to him as I've said now."Since the gun buyback amnesty in 1996, Australians have accumulated over . A conservative by the Australian Crime Commission is that 260,000 of these are illegal.
A policeman holds a military type shotgun - one of over 600,000 guns surrendered in the first Australian gun amnesty (Photo by William West)
Alpha Cheng says he understands the gun used in the attack on his father was from the 'grey market' - originally legal, but then stolen or lost track of before making its way into the wrong hands.
"I acknowledge that there are people that have guns for recreational or agricultural uses, but we need to target those that are using guns for criminal [purposes]."
He stresses the experience hasn't necessarily changed his opinions about guns, and acknowledges the existing laws still have strength.
"My dad often joked that he worked in the safest building in Sydney. So I guess that's, there's some real dark sense of irony there.
But then it shows that it was never something that we were concerned about and part of that is because of the policies and the Howard government brought in."
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