Police in Waikato say they know how Paeroa businessman Jordan Voudouris died, but are refusing to release details because it may prove vital in catching his killer.
He was found lying in an alley behind his restaurant early on Sunday morning.
Detective Senior Sergeant Michael Whitehead says police have now received the interim post mortem results and know how Mr Voudouris, 57, sustained his injuries.
He says the family have been kept informed of developments.
In the meantime, Mr Whitehead says police are continuing to study CCTV footage trying to identify people who were walking or driving through the town at about the time Mr Voudouris was killed.
They are urging anyone who was in the area at the time to contact them.