Nearly one year on since road worker George Taiaroa was gunned down, police say they have made "positive steps" despite not yet making any arrests.
The grandfather was fatally shot as he operated a stop-go sign at roadworks in Atiamuri, near Tokoroa, leading police on a search for a blue Jeep Cherokee seen speeding away.
Police today said an investigation had made "positive steps" in the last 12 months and belief in the theory behind the murder has not wavered.
Although police have not named their prime suspect, it has been widely reported their focus is on Whangamomona man Quinton Winders.
Mr Winders rejected the allegations when approached by a Sunday newspaper last month, reportedly saying: "What they [police] are doing is this big fabrication.:"
Bay of Plenty Police District Crime Manager, Detective Inspector Tim Anderson said it had been "important for the integrity of the investigation from the outset to be patient, thorough, and methodical, and to explore every possible avenue".
"We continue to do that and every avenue we have taken during the last year has simply reinforced our belief about what happened that day and why George was murdered.
"We still believe that the blue Jeep Cherokee vehicle we seized in the weeks following the murder was involved.
"We still have that vehicle and we are continuing to carry out work with that vehicle as part of the investigation.
"Although I am still not prepared to discuss the motive for the murder; our position on that, and the fact that it would appal any reasonable person, has not changed.
"My position also remains the same when it comes to not making comment on individuals; but we still have one prime suspect."
Police wanted to make clear to the public, the person responsible and anyone else who knows or suspects who was involved, that the investigation is still very much active.
"The last year has not been easy for George's family and this week will no doubt be particularly difficult.
"He was a doting family man and the impact of his loss is never far from our minds; it drives us forward and makes us all the more determined.
"As the Taiaroa family has its own private reflection, we ask that the public also reflect on this case and contact us with any information they might have. It doesn't matter how much time has passed or how irrelevant it may seem, it may be important."
*Those with any information regarding the case are asked to phone the investigation team on 0800 Kingswood (0800 546 479). Information can be also provided to the organisation Crimestoppers on 0800 555111.