A leading counter-terrorism investigator says white supremacists pose the greatest terror threat in the world today. Christchurch terror attack: New Zealand falls into silence for two-minutes in tribute to victims Former FBI agent Ali Soufan investigated Al Qaeda attacks including the 2000 bombing of the USS Cole and 9/11. And like Islamic groups, he says the far right has constructed an international network with foreign fighters travelling to conflict zones like Ukraine to fight and become radicalized. The alleged Christchurch gunman says he went to Ukraine, a claim that is currently unverified. As Mike Wesley-Smith reports its just one of many possible lines of inquiries for New Zealand authorities as they scramble to determine whether our darkest day was one we should have seen coming. Newshub Nation.Watch Newshub Nation 9:30am Saturday/10am Sunday on TV3, and follow us on Facebook and Twitter. Newshub Nation is supported by NZ On Air.