Peters told the Herald that Tarrant appeared to be lucid, rational and mentally stable, adding that the shooter may want to use the trial to amplify his views, and it would be up to the trial judge to deal with that.
"But it's not a place for any views to be put forward. It's simply there to determine innocence or guilt. The court is not going to be very sympathetic to him if he wants to use the trial to express his own views", Peters said.
"What did seem apparent to me is he seemed quite clear and lucid, whereas this may seem like very irrational behaviour. He didn't appear to me to be facing any challenges or mental impairment, other than holding fairly extreme views", Peters said as cited by the New Zealand Herald.
Peters stressed that Tarrant had not shown any remorse or regret, but "discussion didn't touch on that".
The shooter's ex-lawyer also added that he had no issues representing Tarrant.
"It's not an everyday event… It's difficult in this case to take a dispassionate view, but you've got to put that to one side and say, 'Right, let's simply process things. My job was simply to appear in court and advise him of his rights and procedure", Peters said.
A violent shooting in two mosques rocked the eastern New Zealand city of Christchurch on Friday, leaving 50 dead and dozens injured. New Zealand's Prime Minister Jacinda Ardern called the shooting a terrorist act, saying it was the country's "darkest day". Tarrant was charged with murder soon after the attack. On Saturday, a New Zealand court ordered that he should remain in custody until 5 April.
According to Bush, following the shooting, police detained a man and a woman after firearms were found in their car. The woman has already been released, while the man has been charged with illegal actions associated with firearms. A third detainee was charged with incitement to racial discrimination and will also face trial on Monday.
Facebook removed as many as 1.5 million video clips depicting the deadly shootings at two mosques in Christchurch, New Zealand over the first 24 hours, with the social network preventing most of the videos from being posted in the first place, according to Mia Garlick, director of policy Australia and New Zealand for Facebook.