Police believe a devastating blaze at a Perthshire mill was started deliberately.
The old Bramblebank building at Blairgowrie, which dates back to the mid-19th Century, went up in flames last weekend.
Around 20 firefighters battled the inferno for nearly 13 hours.
Old Perthshire mill engulfed by flames was targeted by vandals just weeks earlier
We revealed that the riverside property, now owned by soft fruit growers Thomas Thomson (Blairgowrie), had been plagued by vandals, and was last targeted just two weeks earlier.
Now investigators believe Friday night’s fire was started on purpose.
A Police Scotland spokeswoman said: “Officers are treating the fire as suspicious and and investigation is under way.
“Enquiries are ongoing.”
Owners said the building, which was latterly used for storage, could now be “completely lost”.
A spokesman said: “We were saddened at the weekend when our Bramblebank Mill was destroyed by fire.
“We believe a fire was started by vandals, but such was the ferocity of the fire nothing could be saved of the 150-year-old building.
“It was part of the heritage of the town and although it was difficult to see how to develop it for the future, it is very sad to see it reduced to a shell.”
Bramblebank dates back to 1833 and at its peak employed 100 workers, producing flax and tow for the Fife and Forfar trade.
Production was shut down in 1903, and machinery – including a cutting edge condensing engine powered by a turbine – was moved to another mill.
The building was revived by Thomas Thomson in 1948, when it was kitted out with rows of flax spinning machinery.
But in 1963, after a shortage in labour, the company ceased operations at Bramblebank. The building was later used as storage for the firm, which now runs a fruit growing business.
The Scottish Fire and Rescue service said crews were called to the property, off Balmoral Road, just after 9.30pm.
Firefighters used five hose reel jets, floodlights and two ground monitors to tackle the inferno through the night.
They left the scene in the early hours of Saturday, but returned later that morning to carry out a final inspection and check for hidden hot pockets. The fire was finally brought under control at 10.20am.
