"He was going to cut my throat and cut my head off," said an AFP officer who was stabbed five times and recalled Haider standing over him before a single bullet killed the 18-year-old instantly.

A Victoria Police officer, stabbed in the arm but who recovered and shot Haider, ''had no other choice".

''If I had not shot Haider he would have killed [the AFP officer] and then returned to do the same to me," he said.

Haider's actions outside the Endeavour Hills police station, shortly after 7.30pm on September 23, 2014, and his behaviour beforehand were the subject of a coronial inquest that began in early March and finished on Friday afternoon.

Across 13 sitting days, coroner John Olle heard more than 30 witnesses – including counter-terrorism police and security agents – and signed as many suppression orders, given the sensitive material before him.

At the final day's hearing on Friday, the inquest heard that Haider's family was concerned about information provided to the media by Justice Minister Michael Keenan and senior police, including former chief commissioner Ken Lay, in the immediate days after his death and before an investigation.

Megan Fitzgerald, the counsel acting for the family, said then assistant commissioner Luke Cornelius told ABC Radio National the morning after Haider's death: "Our members really had no other choice but to act in the way they did."

She said Mr Keenan told ABC News on the same morning that Haider was a known terror suspect, who carried out an unprovoked attack, and that the officers acted in self-defence.

Ms Fitzgerald said the family did not suggest the coronial investigation was not independent from police but that the comments were premature and could inflame community perceptions that it was not impartial.

Homicide Squad Detective Inspector Mick Hughes said it was inappropriate for him to comment on the senior officer's remarks but agreed pre-judgment of a coronial investigation could have a negative impact.

It is now Mr Olle's job to determine whether Haider was driven by Islamic radicalisation when he attacked Officers A and B, and if so, how young men arrive at that point; or whether Haider was burdened by teenage stresses of parental expectations, a failed romance and unwanted police attention, and snapped.

"I don't think it's an either-or case," terrorism expert Greg Barton told the inquest.

More definitive views depended on who was being asked. Haider's father and eldest brother, who cannot be identified, said they never heard his political opinions but recalled his frustration at having a passport application refused (his parents wanted him to travel with them to Afghanistan to find a wife).

Haider's family fled Afghanistan from the Taliban and described him as a respectful teenager who helped his mother in the kitchen and wanted to be an electrician.

But by September 2014, Australia's national security service believed Haider adhered to an "extreme ideology" given his support online for Islamic State, a desire to fight in Syria and his attendance and associations at the Al-Furqan Islamic Centre. Australian Secret Intelligence Organisation officers earlier visited Haider and urged he stay away from Al-Furqan, a suggestion his parents supported given their disapproval of his "slacker" friends.

On September 18, 2014, angered by counter-terrorism raids in Sydney and Brisbane, Haider waved a Shahada flag at police at Dandenong Plaza. That night, he posted a photograph of himself wearing a balaclava on Facebook, made derogatory remarks about ASIO and the AFP, and warned "brothers" to expect raids like those interstate.

The following day, ASIO officers briefed counter-terrorism police of concerns Haider might engage in politically motivated violence.

Backing this was knowledge of his online searches on Tony Abbott's next prime ministerial visit to Victoria and a remark to a friend he would "do it soon".

ASIO knew Haider had a knife and, a team leader said this week, felt he was on the "trajectory for more extreme behaviour".

A dispute over exactly what information was shared among the agencies in that September 19, 2014, meeting might explain why front-line police were willing to deploy a "disruption strategy" and meet Haider the following week, whereas ASIO officers were not to visit him again. Victorian and AFP officers insist they were never shown by ASIO the provocative Facebook posts, and felt Haider posed no imminent danger.

They told the court had they known, they would have either aborted a meeting or devised a plan different to walking to a dimly-lit car park, where Haider was seated on his car, armed.

Officers A and B planned to discuss Haider's passport, but were also unaware he was furious they had searched his home that day while he was out.

"Dogs came to my house … My stupid parents let them," he told a friend in the hour before the attack, in a phone call not transcribed until afterwards.

ASIO's team leader said she raised the Facebook posts with police, but could not say whether they saw them.

They were publicly accessible, she said, and police knew Haider's account.

Countering that, a senior police officer wrote "Facebook rhetoric" in his notes in reference to what was discussed, and said the posts were critical, but unseen.

Homicide squad detectives tried to access Haider's Facebook messages as part of their investigation into his death, but were unable to find the correct passwords.

Under questioning, Leading Senior Constable Leigh Smyth said getting a search warrant to get Facebook to hand over the messages could take up to two years.

Haider's family raised concerns as to why detectives did not access the messages using his mobile phone. Unless there is a lock on phones – and Haider's didn't have one – the Facebook and Facebook Messenger apps are often accessible as they usually don't require a password to log in.

Leading Senior Constable Smyth said he was not sure whether the apps were logged into on Haider's phone, but if they had been it would have been illegal for him to look at them without getting prior permission from his superintendent, which could take up to eight weeks. He said this step was not taken.

Critical also is what was driving Haider at the end. His ex-girlfriend, who saw Haider just once after their July 2014 break-up, could not explain his ultimate anger.

"In the time we were not talking something happened," she said.

Exactly what is for the coroner in his findings.