New Zealand authorities were so worried about an extremist inspired by global terror groups they were following him around-the-clock.
They were able to shoot and kill the man within 60 seconds of him unleashing a frenzied knife attack on shoppers in a supermarket.
New Zealand Prime Minister Jacinda Ardern says that three of six people who were stabbed were seriously injured.
Ardern says the man was a Sri Lankan national who was inspired by the Islamic State group.