Police have confirmed no one was inside a central Whanganui building - known to be sometimes occupied by squatters - when it was destroyed by fire in the early hours of Monday morning.
A police spokesperson said the investigation into the fire was ongoing and it continued to be treated as "unexplained".
"Police is liaising with Fire and Emergency New Zealand in the investigation."
The two-storey building on Victoria Ave was gutted from the inside leaving just a central brick wall and facade which was pulled down on Tuesday for safety reasons.
The fire started just before 3am on Monday and produced a glow in the sky which firefighters could see as they left Whanganui Fire Station for the scene.