Thirty-three year-old David Gray began shooting after a confrontation with one of his neighbours over a dog.
By the end of his rampage, 13 people were dead and several others were injured.
The police's anti-terrorism squad was sent in to stop David Gray's shooting rampage. Photo: 123RF
It is New Zealand's second deadliest mass shooting, after the Christchurch mosque attacks which saw 51 people killed.
Tim Ashton was a member of the Anti-Terrorist Squad who was sent in to stop Gray. He shares his recollections of the day and his subsequent battle to change gun legislation.
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