Police in the Far North have confirmed they are now treating a recent fire on the Karikari peninsula as arson.
Two men died when a helicopter crashed into the sea off Karikari beach on 30 November.
Detective Inspector Karyn Malthus says the police have completed a detailed scene examination and eliminated any natural cause for the fire.
She says the area is a secluded piece of private Maori land - but the gate was unlocked on the day of the fire, allowing unrestricted access.
Detective Inspector Malthus says police have spoken to a number of residents, but they want anyone else who was in the area that day, or knew of someone who was, to come forward.