With no sight of the offender and growing crowds confusing the scene at a late-night teen stabbing, you'd think police might have had a hard time finding the attacker.
But enter 4-year-old police dog Link - small for his breed, but a powerful tracker.
The german shepherd, who in May came third in the national police dog championships, picked up the scent of the alleged offender, tracking him almost 2 kilometres down roads and back alleys from Waitangirua Mall, eventually to find him holed up on the roof of the Mongrel Mob headquarters.
It was one of Link's most successful jobs, handler Constable Stu Rota said, particularly in tough tracking conditions over such a long distance.
"I've been doing this for three or four years and I'm amazed by the dog. Something like that just blew me away. It was just shy of 2km.
"If you're in the bush it's money for jam, the trail lingers ... but when you're on a hard surface [in urban environments] the scent just dissipates."
The Mongrel Mob HQ was only about 150 metres from the scene of the stabbing, but the offender took a circuitous route, running down alleys and jumping fences.
"He's sort of taken a massive loop, taking walkways. I didn't know where we were going at the beginning ... but that last walkway we were coming down, we were going towards the [gang] pad."
When they reached the Commerce Cres gang pad, they called in reinforcements to cordon off and search the building, Mr Rota said.
"There was no-one inside the building but, as we were leaving, the dog indicated the fence, which suggested the guy had gone up.
"He would have heard us clearing the building. I looked up and he was running right towards me on the roof. It was too high to jump down ... and I challenged him and managed to talk him down.
"One of the other coppers jumped up on the roof and found the knife."
The teen was arrested.
It was a job well done for Link, but Mr Rota wasn't surprised that his "best friend" came through.
"It was a really good job for the dog. I was really, really happy with his work. For the level of offending and the way in which he tracked, that was definitely one of his better tracks."
- © Fairfax NZ News