The fact there was no power to the place and it was “supposedly secure” led him to that conclusion, he said.
He went to the fire around 1.30am Sunday and returned during daylight to carry out his investigation.
There were reportedly squatters living near the building though it is not yet known who was responsible for the incident. There were no reports of injuries.
Bain said no matter the circumstances, people have “no right” to deliberately set a fire.
A resident whose home overlooks Beach Rd said they saw a “glow” in the sky just after midnight but thought it was firecrackers.
They had observed graffiti on the building regularly and said it usually looked “very unkept”.
They were shocked to hear it had burned down overnight.
Other Onerahi locals flocked to the site on Sunday morning having heard about the incident through Facebook community pages and word-of-mouth.
The smell of ash lingered in the air even hours after the fire had been extinguished. Graffiti was still visible on one wall of the building which sat burned and unsteady.
Those who spoke to the Advocate said they were saddened to hear of the building’s demise but were not surprised to see it go down in flames.
One resident said he heard about the fire on a community page and thought he would go and have a look.
“It’s a bit of a shame. I grew up here and it’s always been here. The sea scouts used to run a mean operation out of it.”
However, he said the building had been “abandoned for years” and the target of repeated vandalism.
Another local heard about the fire through a friend and said it was “sad” to see the landmark that’s been there for “so long” go.
Broken windows and rubbish dumped nearby were not an uncommon sight, residents also noted.
Brodie Stone is the education and general news reporter at the Advocate. Brodie has spent most of her life in Whangārei and is passionate about delving into issues that matter to Northlanders and beyond.