The coroner's inquest into the mosque terror attacks, in which 51 people were killed, will look into the role of social media in the killer's radicalisation, and the emergency response on the day.
Coroner Brigitte Windley has released the scope of what will, and won't, be covered in the upcoming coronial inquest.
In February a hearing was held to hear submissions from interested parties - including people injured in the attack, family members of those killed, and community organisations - about what they would like to see covered in the inquest.
In her decision released on Thursday Windley said the atrocities of 15 March 2019 were unprecedented in New Zealand, as is the nature and scale of the coronial inquiry.
The inquest will look at the events from the start of the attack until the completion of the emergency response.
This will include whether the killer, Brenton Tarrant, got any help from others, the emergency response efforts, and if that response resulted in anyone not surviving their injuries.
It will also look at the terrorist's radicalisation through social media and online platforms.
Windley said this was an issue identified as a particular concern by the interested parties.
She said the Royal Commission of Inquiry into the attacks had only looked at the terrorist's online activity from 2017 until the attacks, whereas she will particularly focus on 2014 to 2017.
"Any effort to go further than the Royal Commission did to isolate any specific online platform or influence as sufficiently causally [and quantifiably] linked with [the terrorist's] radicalisation [and therefore with the attack], is likely to encounter formidable evidential challenges.
"That said, the potential that a sufficient causative link may yet be possible to establish cannot be ruled out without first making additional inquiries."
The coroner said how the terrorist got his firearms licence was also an issue of particular concern for the interested parties, and this will be looked into.
She said the issue was looked at by the Royal Commission but source evidence about the link between the terrorist's firearms licence and how he caused the 51 deaths was not available to interested parties to see and to consider, but can be as part of the coronial inquiry.
The inquest will also look at the community's ability to detect radicalisation and respond. Windley will look into the line of defence that the wider community may provide as one means of future prevention.
She will also look into the cause of death of each person killed.
Probe of intelligence agencies ruled out
The coroner said the interested parties had asked the coroner to investigate whether intelligence and counter-terrorism agencies in particular had missed any opportunities to prevent the attack but that this was outside her scope.
She said the issue was extensively looked at by the Royal Commission, and, due to the sensitive nature of the evidence, it was unlikely she would be able to release any information not already available.
She will also not look into issues deemed too speculative and remote, including whether the terrorist's international travels led to his radicalisation, and New Zealand's immigration policy.
The national coordinator for the Islamic Women's council, Aliya Danzeisen, said the decision to look at online platforms and social media's role in the attacks is a landmark moment for the accountability of digital platforms.
She said they want to know where the terrorist was going online, who he was speaking to and what was being presented to him.
"This was a decision he made, but we want to know the environment he was in, and we want to learn so if parents are seeing things, or if the community need to learn so we can get in front of it. But also do the social media companies need to learn from what occurred?
"The coroner has opened the door to investigating the responsibility of social media platforms like Facebook and Twitter, other sites like YouTube, and gaming messaging forums," Danzeisen said.
"It is becoming increasingly clear that digital platforms need to do more to prevent the circulation of dehumanising content, and this decision should be a wake-up call to those platforms.
"Federation of Islamic Associations chair Abdur Razzaq said the coroner had listened to the requests from the victims and families of those killed.
Razzaq said he was optimistic the inquiry was shaping up to provide significant lessons for the community, and some sort of closure to all of those affected by unanswered questions.
He said they were particularly pleased to see the issuing of the firearms licence to the killer will be looked into.
No date has been set yet for the inquest.