Police are still unable to say what caused the early morning fire which destroyed a historical Victoria Ave property last month.
The two-storey building was gutted from the inside leaving just a central brick wall and facade which had to be demolished the following day.
A police spokesperson said on Thursday "the investigation into the fire is ongoing and there's no update at this stage".
The fire started just before 3am on October 29 and required every available firefighter in Whanganui to help fight the blaze.
The building, opposite Plymouth St on Victoria Ave, is owned by the Tupoho trust, has been unoccupied for several years and was already slated for demolition.
Last week police have confirmed no one was inside a central Whanganui building - known to be sometimes occupied by squatters - when it was destroyed.
The fire was being treated then as "unexplained".