"But that arrest was tangential to this matter and we do not believe that he was involved in this attack either", he said.
He has so far been charged with one count of murder, although judge Paul Kellar said it's "reasonable to assume" that more charges will follow, after yesterday's deadly shooting.
Tarrant was also purportedly inspired to commit the mosque shootings by Norwegian far-right terrorist Anders Breivik, who killed 77 people in Oslo in 2011.
On Friday, Ardern characterized the incident as a terrorist act.
A message card is placed at a collection of flowers left at the Botanical Gardens in Christchurch, New Zealand, Saturday, March 16, 2019.
The staff member monitoring the accounts sent it to parliamentary services as soon as they saw it, who sent it to police, the spokesman said.
Church services for victims of the attack were held around the country, including at Christchurch's "Cardboard Cathedral", a temporary structure built after much of the central city was destroyed in a 2011 natural disaster.
He said Saturday that the six confirmed dead include 48-year-old Naeem Rashid and his 21-year-old son, Talha Naeem.
None of those arrested had a criminal history or were on watchlists in New Zealand or Australia.
During the Saturday morning hearing, a man who was not in court was charged with using writings to incite hatred against a race or ethnicity, but it was not clear if his case was related to the mosque attacks.
"New Zealanders are devastated", Jackson said in a statement to Variety.
The victims of Friday's shooting included immigrants from Jordan, Saudi Arabia, Turkey, Indonesia, and Malaysia.
Police urged all mosques across New Zealand to stay closed over the weekend for security reasons.
New Zealand has previously tried to change its gun laws, with the most recent attempt coming two years ago. The minimum legal age to own a gun in New Zealand is 16, or 18 for military-style semi-automatic weapons.
Business Standard reports that Tarrant allegedly used "two semi-automatic rifles, two shotguns and a lever-action weapon".
"I was one of more than 30 recipients of the manifesto that was mailed out nine minutes before the attack took place", Ms Ardern told reporters on Sunday.
"Unfortunately, we are all too familiar with the devastating effect a mass shooting has on a faith community", said Meryl Ainsman, chair of the board of the Jewish Federation of Greater Pittsburgh.
"You may have chosen us", Ardern said, addressing the suspect.
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