Australia's only civilian casualty in the war in Afghanistan has cast doubt on a Defence investigation into a 2012 suicide bombing in Uruzgan that almost killed him, labelling the inquiry a "perversion of justice" that ignored key evidence in order to protect the military's reputation.

Key points: Australian David Savage was in Afghanistan as an AusAid adviser in 2012

Australian David Savage was in Afghanistan as an AusAid adviser in 2012 He was severely injured by a suicide bomber in Uruzgan

He was severely injured by a suicide bomber in Uruzgan Mr Savage says a Defence investigation into the incident ignored crucial evidence

Speaking out for the first time about the attack, former federal police officer and UN war crimes investigator David Savage says he was shocked by the investigation.

This is not the first time a Defence inquiry into the wounding or death of Australians in Afghanistan has been criticised for fundamental failures. In 2014 the families of three Australian soldiers killed at Patrol Base Wahab rejected the findings of a similar internal inquiry, saying it also overlooked key evidence.

Mr Savage says he has spent almost eight years asking the Australian military and the Department of Defence to acknowledge a series of errors in the run-up to the attack but has been stonewalled.

He now feels compelled to speak out about the inquiry, which he says was marked by obfuscation and falsehoods.

"I've got a responsibility, because if they've done this to me in such a high-profile case, being the only civilian, what are they doing to other young soldiers that have been injured or have been killed and their families are trying to find out what happened — how do they get justice?" Mr Savage said.

He says the similarities between his case and the Patrol Base Wahab are concerning — both were investigated by the same Australian Army officer — and may suggest defects in his inquiry are a systemic problem.

"How can you have any faith in anything that Defence does in their inquiries … if their fallback position seems to be to lie and cover up?"

'I actually thought I was dead'

David Savage, right, lies injured on the ground after the blast. ( Supplied: David Savage )

Mr Savage was almost killed by a 12-year-old suicide bomber on March 26, 2012, while serving as an AusAid stabilisation adviser in the Chora Valley, Uruzgan. The remote, volatile province was under the security mandate of an Australian-led international military force at the time.

An Australian surgeon later likened Mr Savage's wounds to being shot eight times with a shotgun at close range. He was hit with 64 ball bearings and pieces of shrapnel, as well as a traumatic brain injury and deep psychological scars.

The Canberra man remains in a wheelchair and has not been able to work since the attack. His wife had to quit her job to become his fulltime carer.

Two US servicemembers — a Navy medic and an army captain — were also badly wounded in the attack.

The three were serving as part of a mixed civilian and military unit called a Provincial Reconstruction Team (PRT) that was assigned to the Chora Valley to help rebuild after decades of war.

The PRT was returning from a visit to the district governor when, about 100 metres from home, a 12-year-old boy dressed in white calmly walked into the patrol.

An explosive device strapped to his torso was then detonated, hurling Mr Savage and the two US soldiers metres across the road and leaving a 12-metre-high plume of white smoke.

The wounded medic attempted to treat Mr Savage before he also collapsed.

"At first, I actually thought that I was dead. [The medic] had gone out of my line of sight and I wasn't in any pain whatsoever," Mr Savage said.

"And I thought I must have died. And this is what it's like."

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Missed signs

US soldiers tend to David Savage's wounds after the bomb blast. ( ABC News )

As Mr Savage lay there he recalled the signs of the impending attack he believes the patrol missed.

He later managed to obtain a copy of footage from a helmet camera which shows the entire patrol from the vantage point of the US Navy sergeant assigned to guard him.

The video, which the ABC has seen, reveals a number of signs which are considered indicators of an impending attack, including:

The appearance of the young suicide bomber wearing pristine white clothes — signs coalition soldiers were told to watch for.

The appearance of the young suicide bomber wearing pristine white clothes — signs coalition soldiers were told to watch for. A local walking past the patrol with hands stained a vivid orange, which can be an indication of the handling of home-made explosives.

A local walking past the patrol with hands stained a vivid orange, which can be an indication of the handling of home-made explosives. A group of labourers near the attack site abruptly leaving their worksite without their tools.

'Attitude was adversarial'

About three weeks after the attack, Defence ordered an internal probe — known as an Inquiry Officer Inquiry — to examine the incident.

The inquiry was given broad ambit according to its terms of reference, which include examining whether there were any "deficiencies or weaknesses" in: the manner in which Mr Savage was protected by the US military members of the PRT; and in the intelligence support provided to the PRT.

Mr Savage was interviewed several months later by the inquiry officer and his assistant.

"I thought that the focus of their investigation would be on how I — protected by a US security detachment — was able to be blown up," Mr Savage said.

"[But] when the two investigators came, their attitude from the beginning was really adversarial."

They appeared to be more interested in that fact Mr Savage had been wearing non-ADF body armour provided to him by a US soldier because his ADF-issued body armour did not fit him.

"They didn't seem to want to know anything about what had happened or how I got blown up or anything like that, it was just focussed on the fact that I wasn't wearing an ADF ballistic vest."

'Multiple reports of suicide bombers being trained'

Former Army combat engineer officer Chris Thompson-Lang. ( ABC News )

The Defence report was provided to Mr Savage soon after. It was highly critical of him and entirely exonerated both the US soldiers guarding him and the Australian Defence Force.

"The attack was an unexpected event," stated the report, which refers to the attack as a Person-Borne Improvised Explosive Device, or PBIED.

"[T]he patrol did not detect any threat prior to the PBIED detonation. More broadly, there had been no intelligence warnings of such a threat."

Mr Savage knew the patrol had noticed warnings signs and could prove it because he had a copy of the helmet camera footage.

He also knew the statement about a lack of intelligence warnings was also incorrect because an Australian officer he had befriended at the Chora Valley patrol base had seen intelligence saying the opposite.

"We'd had multiple reports of suicide bombers being trained," former Army combat engineer officer Chris Thompson-Lang told the ABC.

"And there were reports of two 12-year-old children being prepared for Chora right through the time that I was there. For as long as I could remember, there were reports coming in."

Mr Thomson-Lang recalls seeing the last intelligence report about the two 12-year-olds in January, only two months before Mr Savage was attacked, and has no reason to believe that threat subsequently ceased.

"The nature of intelligence is that you get snippets of information when you can from the sources that you have.

"It doesn't necessarily mean that it's going to happen straight away … that threat was persistent. [We weren't] going to get a tip-off the day of [an attack]. That's unrealistic," he said.

Despite that, when the report landed it stated: "There were no shortfalls in the analysis or provision of intelligence advice or products to the PRT."

Before the attack, the report stated, "There had been no credible or specific reporting to indicate any likelihood of a PBIED attack in the Chora district against such a target as the PRT."

Mr Thompson-Lang read the inquiry report and was angered by the finding regarding intelligence support. "I just think that it's an arse-covering. A cop-out," he said.

"I thought that it was highly likely that the child that blew David up was one of the two that had been reported while I was there and one of the two that we'd been looking for."

Former SAS soldier disagrees with report findings

David Savage when he was a UN police officer. ( Supplied: David Savage )

Mr Savage repeatedly asked Defence to re-examine the helmet camera footage but they refused.

That refusal was made even more frustrating when Mr Savage discovered that soon after the attack, Defence had begun using elements of it as a visual aid during a formal induction course for civilians about to work with the Australian military in Afghanistan.

Mr Savage eventually asked a former senior non-commissioned officer from Australia's pre-eminent combat regiment, the SAS, to review the footage.

The former SAS soldier, whom the ABC has agreed not to name, found that based on the helmet camera footage the US patrol "appeared to lack discipline and wandered from their tasks". He described their response to the attack as "delayed and disjointed".

The former SAS soldier stated the stained hands of the local and the departure of the labourers were both "critical pieces of information" that should have been acted upon.

"The major sign of an impending attack in Afghanistan was civilians hastily departing an area," the former SAS soldier stated. "This was well-known by coalition forces."

He also found the patrol should have identified the suicide bomber and failed to take appropriate action to protect Mr Savage.

The former SAS soldier disagreed with some of the most fundamental findings of Defence's inquiry report, including that the US patrol was experienced and professional, that there was nothing they could have done to prevent the attack, and that there were not "shortfalls" with the patrol's tactics.

"The US [patrol] appeared unable to identify potential threats, possibly due to a lack of training and inexperience," the former SAS soldier said.

"I believe that an Australian infantry patrol would have performed better and identified the threats shown on the video, enabling the opportunity to prevent the attack."

The ABC sent a list of questions to Defence which they declined to answer, instead providing a statement from a media spokesperson.

"The ADF is confident that due process was followed," the statement read.

"The [inquiry] report did not identify any shortfalls with the US security force tactics, techniques and procedures prior to the mission on 26 March 2012.

"The actions taken by the United States security force immediately after the incident may have saved Mr Savage's life."

'It eats you up'

David Savage has not been able to work since the attack. ( ABC News: David Maguire )

"They clearly had an outcome of their inquiry that they wanted to achieve, which was that there was no blame for Defence … and they constructed the investigation to ensure that outcome," Mr Savage said.

And his concerns about the inquiry were increased when he discovered that an incident in August 2012 — five months after his attack — that resulted in the deaths of three Australian soldiers was investigated by the same Army officer and had led to the same claims of cover-up and obfuscation.

The soldiers, Lance Corporal Stjepan Milosevic, Sapper James Martin and Private Robert Poate, were killed by a rogue Afghan National Army sergeant named Hekmatullah at the Wahab patrol base in Uruzgan.

The Defence inquiry report in that case also focused blame on the victims and those around them.

A subsequent Queensland coronial inquiry found that, in fact, there were systemic failures by Defence leadership.

"I've worked on some of the most egregious war crimes, trying to seek justice for victims, and I've spent the last seven years … trying to get justice for myself from my own government," Mr Savage said.

"They use every means possible to prevent you getting justice and prevent the truth from being told.

"It delays your recovery. It eats you up. It's psychologically destroying. They make out that, 'Oh, you're just some bitter nut job that got injured in a war zone and is now complaining about it.'"

Mr Savage says he always knew there was a risk he would be wounded or killed by working in Afghanistan.

"But never in my wildest dreams would I think that I'd get wounded [and] my own country would damage me even further by covering up what occurred."

Watch this story tonight on 7.30.