Firefighters have returned to the seen of yesterday’s blaze at Strathmartine Hospital.
Investigators are trying to establish if the fire at the former hospital, on the edge of Dundee, was started deliberately.
Five engines and dozens of firefighters tackled the blaze, which started at about 1.40pm.
The fire was under control after a matter of hours, and crews remained on scene from 5pm to dampen down the site and was fully extinguished this morning.
Police Scotland are awaiting the results of the investigation before pursuing any lines of inquiry.