A town centre fire that broke out seven weeks ago is now being treated as arson, police say.
The blaze in a disused building started in the early hours of 30 March in Sheep Street, Northampton.
Nine fire crews were called to the site to tackle the flames and nearby roads were closed.
West Northamptonshire Council said it was discussing the demolition of the building with the owner.
The fire-hit building, at the junction of Sheep Street and Church Lane, was occupied by an ex-servicemen's club but has been empty for a few years.
The emergency services were called at 05:50 BST on March 30.
People living nearby were told to keep their windows and doors shut because the fire had generated a large plume of smoke.
Some nearby properties lost power while the incident was dealt with.
Seven weeks later, the police have told the BBC the investigation is ongoing and the fire is being treated as arson.
Thomas Manning, West Northamptonshire Council's cabinet member for planning and communities, said: "We have had discussions with the building's owner to inform them of what the actions they need to take regarding the demolition of the building.
"We've been assured that they are now working through those actions."
The BBC is attempting to contact the building's owners.
The building dates from the 18th Century and was once the home of William Kerr, who founded Northampton General Hospital.
The adjacent property, Kerr House, was given to the Corporation of Northampton in 1683, which leased it to tenants.
It was described in 1828 as "a mansion-house, garden, stables, coach house and pleasure-ground".