A major air and sea rescue operation was mounted on Tuesday night after witnesses spotted a car underwater in the River Tay.
Emergency crews were scrambled to a sewage plant near Perth amid fears someone was trapped inside the vehicle.
Firefighters took to the river in a rescue boat to reach the submerged red Renault.
A coastguard helicopter and lifeboat crew from Broughty Ferry also joined the search.
However, mercy teams were stood down after about an hour when it was confirmed the car was empty.
Locals believe the vehicle may have rolled down the banks several hours earlier, perhaps even the night before.
It is thought the car had been pulled by the current to its resting place, overlooking Walnut Grove.
Efforts are being made to identify the car’s owner.
Several fire appliances were parked at the river’s edge during the operation which was launched shortly before 5pm on Tuesday.
Coastguard crews, police and paramedics were also called to the scene.
An ambulance accident response unit was on stand-by.
Speaking at the scene, Perth-based Inspector David Hynd said: “The car was spotted in the water by a worker and there was concern someone could still have been inside.
“Once the search was under way it quickly became clear that there was nobody in the vehicle. It was secured and we carried out a search in the water around it.
“The coastguard helicopter was called and carried out a search just to be sure.”
Insp Hynd said efforts would be made to recover the car from the river.
One onlooker said: “It was a huge operation. When I saw the amount of fire engines, it looked like something very serious had happened.
“It’s a relief to know that no one has been hurt.”
Police believe the car entered the water from another part of the riverbank.
Anyone who can help trace the car’s owner has been urged to contact police.