In the "manifesto" the suspect describes U.S. President Donald Trump as a symbol of renewed white identity.
When Trump asked Ardern what he could do to help, she told him to show "sympathy and love for all Muslim communities."
So what's driving the hatred and prejudice against Muslims in Western countries? And is it linked to white supremacy?
Presenter: Hazem Sika | Guests: Tasneem Chopra, chair of the Australian Muslim Women's Centre for Human Rights; Rodger Shanahan, research fellow at the Lowy Institute; Matthew Goodwin, professor at the University of Kent and former member of the UK government's Anti-Muslim Hatred Working Group.