The low key meeting outside a suburban police station that left two police injured and Muslim teenager Numan Haider dead is the reality of the terror threat in Australia.

While the headlines tend to be devoted to big picture targets such as Parliament House and the MCG, counter-terrorism police are more concerned about irrational lone offenders who launch random attacks with little or no planning.

The organisations to fear are those that are not organised and therefore difficult to identify.

Unlike organised crime investigations you cannot follow a recognised structure to the leaders, build a network of informers or rely on traditional undercover methods.

Most of the home-grown radicals are vulnerable to ideological doggerel because it fills a void in their unsatisfactory lives. They look to place blame and international terror groups can act as a lightning rod for their anger.

Police say they are either recruited by word of mouth or fall in through radical propaganda easily accessible through internet sites and it can be a disturbingly quick process.

A Dandenong trader was shocked recently when he started chatting with an Australian-born Muslim youth too young to grow a traditional beard.

"He said he wanted to burn Australia to the ground, blow up trains and behead taxi drivers."

In Britain, authorities are working to find out why so many UK Muslim youths have disengaged with their own society to take up the doctrine of groups such as Islamic State.

The 18-year-old man had agreed to meet police at the Endeavour Hills police station because of growing concerns about his recent behaviour.

While counter-terrorism police were monitoring him, he was not considered a major threat, which is why he was invited to meet police.

It is part of a deliberate policy not to escalate tensions by conducting forced raids unless the suspects are considered dangerous.

"If we had gone in and dragged him out of his home we could have looked like stormtroopers," a senior policeman told Fairfax Media.

The Endeavour Hills attack will heighten police concerns for their own safety when dealing with potential terror suspects.

History shows in Victoria that a police shooting in Victoria is often followed by another within days involving a copycat crime.

Within 12 hours of the death, police had received intelligence that men close to the dead teenager were "very angry".

Chief Commissioner Ken Lay is desperate to avoid an "us against them" mentality that can only increase the risk of violence.

Police have built strong links with local Muslim leaders but the trouble is the radicals have turned their backs on their own elders, preferring the hate rants of a tiny minority.

Police experts say an opportunistic attack involving an individual or small group is more likely than an organised one on a major target.

They point to the murder of British soldier Lee Rigby who was attacked and killed outside London Royal Artillery Barracks in May last year.

It is no coincidence that as reported last week, some Australian Defence Force commanding officers have advised personnel not to wear their uniforms to and from work and on public transport due to the increased terror risk.

It is expected police patrolling areas with large Muslim populations will be briefed to be vigilant to potential payback hate crimes against Islamic communities.

Within hours of the Endeavour Hills incident, many media outlets received a series of provocative texts and emails blaming the broader Muslim community for the stabbings of the two police officers.

And yet the biggest terror attack in Victoria, the 1986 Russell Street Police Station car bombing that killed Constable Angela Taylor and left 21 people injured, was not committed by a radical religious group but by local white trailer-trash.