Police say the motive for killing road worker George Taiaroa is disturbing.
The investigation team's released more details about the case today, saying they have a suspect, and believe he's being hidden.
Detective Inspector Tim Anderson says the killer had a misguided motive.
"What I can say is this killer had a reason for the killing. It's probably a reason that would appal most or any reasonable person."
Detective Inspector Anderson says someone is hiding information about the killer out of some misplaced sense of loyalty.
"There's a handful of others out there that know what this killer knows, and we're interested to hear from them."
He says police won't hesitate to prosecute anyone found to be assisting, aiding or encouraging the suspect.