They say their son Travis Cashmore, 45, felt compelled to act because of wholesale failings in the criminal justice system.

Parents Ron and Dot Cashmore are now angry and want the cost of their son's life to spark change.

They want those who repeatedly breach intervention orders to be treated like serious sex offenders - where protection of the community becomes a priority.

They have called for similar accumulation in sentencing and requested that those again charged with intervention order breaches show exceptional circumstances before being granted bail.

At 10.23am on July 22 Travis Cashmore pulled out a sawn-off shotgun and killed career criminal Kevin Knowles, 49, before shooting and running down sidekick Benny Ray, 48, on the side of Scotts North Road at Kirkstall.

He then returned to his home where he took his own life 16 minutes after the initial shootings.

The Cashmores found their son in the rear yard of his home three hours after the killings.

They have maintained a dignified low profile, letting the community be their voice in the fallout from the double murder/suicide.

But grief has now turned to anger when they realise their son made the ultimate sacrifice to free his community from a lawless tyrant and standover man.

The Cashmores claim the justice system failed them, their son and the Kirkstall community.

They say they have been approached almost daily since the killings by people expressing sympathy and support.

The Cashmores have heard stories of Knowles standing over shopkeepers, terrifying neighbours, threatening to kill Kirkstall residents and women refusing to stay at their Kirkstall homes alone.

Mr Cashmore said he had found a piece of metal tubing in a sink beside his son's back door and other makeshift weapons near other points of entry and around the property.

Neighbours have told the Cashmores their own protection strategies.

"Everyone had a strategy to protect themselves against Knowles, who was always armed," Mr Cashmore said.

"For the last six months of Trav's life he worked with me, side by side. He was a highly gifted welder and could turn his hand to anything.

"Trav feared Knowles and Knowles was a constant topic of conversation.

"The way Knowles intimidated, stalked and harassed Kirkstall residents greatly frustrated Trav.

"The failure of the criminal justice system to protect the community, to protect his friends in the end proved too much - and Trav took action."

Mr and Mrs Cashmore feel the loss of their son every day - in a million different ways.

Their grief surrounds them - as does their undying love for their son.

They agree they want one thing - that no parents ever go through what they are enduring.

They want change.

There has been much said about Knowles and his connections to the deaths of up to five people.

He spent a couple of days in custody while homicide squad detectives interviewed him over the death of Warrnambool's Steve Johnston and he ended up the only suspect.

Knowles knew the law, he knew how to minimise his crimes and how to get the lightest possible jail sentences.

But his greatest personality flaw was not allowing others to live their lives in peace - he was relentless and ultimately it cost him his own life.

Court imposed Intervention orders were an inconvenience that could be circumvented through intimidation - if no one complained, there was no breach, there was no crime.

Knowles had almost 300 prior court convictions, the majority related to intervention order breaches.

Three days after his death Knowles was due to face Warrnambool court on three more charges of breaching orders and one count of persistently breaching the order.

In January this year Knowles was jailed for threatening one of Cashmore's friends while armed with a knife.

"I'm going to kill you and your kids, your days are numbered," Knowles said.

In the days before his murder Knowles returned to that same victim's home.

Cashmore was at his friend's home helping with a shed on the Tuesday afternoon, he took video footage of Knowles walking past clearly in breach of an order, who growls "how's ya mate going?"

Cashmore the next day went to the Koroit police station and reported the breach but was told the friend needed to make a statement.

Cashmore told two police officers something along the lines of "leave your gun on the counter and I'll take care of him".

The police recalled Cashmore appeared frustrated.

On Thursday Cashmore ran over shopping belonging to Knowles and Ray that was left on the Kirkstall-Koroit Road.

At 7.30am Friday a concerned Trav Cashmore rang his father after a sleepless night and appeared set on a course of action.

He trimmed some regrowth on a neighbour's bordering blue gums and at 9.53am he's captured on security camera footage buying Tattslotto tickets for his mum.

Twenty minutes after leaving the shop Knowles and Ray are dead on the side of Scott's North Road.

The Kirkstall community is free of the standover man, but at what cost?

Mr and Mrs Cashmore are among those who will forever pay for that freedom.

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