Edinburgh Zoo was put on escape alert after teenagers tried to break into a tiger enclosure.
Sasha was one of the Amur tigers in the enclosure
The three youths were chased out of the zoo by security staff who had become aware of a disturbance.
However, a zoo spokesman said they discovered the lock on a door into the enclosure holding Amur tigers had been tampered with.
The animal escape alert was instigated as a precaution but the tigers were found to be still inside the pen.
The break-in happened at about 1830 GMT on Sunday.
Iain Valentine, head of animals, education and conservation at Edinburgh Zoo, said: "It is extremely unlikely that anyone could get inside as there are several doors to penetrate, all with individual locks and padlocks."
He added that the animal escape procedure was activated as a precaution and that no staff were at risk at any time.
"The tigers were found safe and well, inside their indoor den, wondering what all the fuss was about," he added.
A spokesman for Lothian and Borders Police urged anyone who saw anything suspicious to contact them.
Amur tigers, also known as Siberian tigers, are the largest cats in the world.
Four years ago, a man was discovered in Edinburgh Zoo's penguin enclosure in the early hours of the morning, while in 2000 two panther chameleons were stolen in an overnight break-in.