Detective Inspector Kevin Burke said ESR staff were called from Auckland to carry out scene examinations at both addresses and also at the Whangarei St John Ambulance Station.
"Police are still working to establish the circumstances surrounding this man's death.
"We are asking any members of the public who may have witnessed a group of men gathered in the Whangarei or Kamo areas in the early hours of this morning to contact Whangarei Police," Mr Burke said.
He said police would not release the victim's name until formal identification had taken place.
A post-mortem would be carried out tomorrow.
Meanwhile, an officer toting a hefty firearm kept a close eye on the scene outside Northland ambulance headquarters as upset family members converged at the cordon.
They began to gather shortly after word spread that the man - who had been taken by car to the station in a critical condition - had died. Police were called and quickly put up police tape about 6.40am.
As whanau arrived and parked on the side of Western Hills Drive, there was hugging and crying. One family member said the shock was still sinking in.
Another woman pushing a pram with two young children left the scene in tears.
Neighbours in the area were unsure what was happening but some had their suspicions when they saw one man with blood-stained clothing.
"I came out to open up my front gate and collect the paper and I saw the police over there," said one neighbour.
"They've taken one man away in a police car so I'm not sure what is happening."
While officers guarded the scene others paid particular attention to a silver Mercedes car in the middle of the cordon which had a gang vest resting on the bonnet.
