Members of the criminal underworld have helped detectives investigating George Taiaroa's murder.
Detective Inspector Tim Anderson, leading the investigation, said "the usual suspects" had provided information that helped narrow the search considerably early on.
Today marks one year since Mr Taiaroa, 67, was gunned down as he operated a stop-go sign on Tram Rd, near Atiamuri. Mr Anderson said they were confident the man they believed responsible was the right person but would not rush an arrest.
"We have been very thorough and meticulous and also patient in an inquiry like this," Mr Anderson said. "Most homicides are domestic, drug, gang or alcohol-related. This doesn't fall into any of those.
"What has fallen in our favour is that we've amassed a lot of information from the public, and we're very thankful for that. Our usual suspects have also come in and alibied themselves, which has allowed us to narrow our focus and that doesn't always happen."