Forensic psychologist Devon Polaschek said that from the evidence of Tarrant’s PDF document she doesn’t believe he is psychotic.
"He has spent far too long ruminating on certain ideas - but those ideas are shared by others," she said.
Dr Polaschek, who is also Joint Director of the NZ Institute of Security and Crime Science, says Tarrant falls clearly into a group of young white men susceptible to "errors of thinking".
"From what I have seen he typifies a segment of the population at risk of terrorism - working class European young men, who are vulnerable to feeling redundant, and can’t engage with any of the great things happening in society."
She said Tarrant did not expect to die in the attack, and that his document has many contradictions and hypocrisies.
Christchurch terror attack: Life of alleged killer Brenton Tarrant | Newshub