"There was a lot of damage. Brick work has been taken out all over the place. There is nothing wrong with the overall structure though.
"The council are involved to see if a crime has been committed because it's a Grade II listed building.
When the artwork first appeared on the 300,000 terraced house a bidding war ensued - with the council boarding up the wall to prevent vandalism.
After Kaveh agreed on a price for the house, the boarding was taken down so that people could enjoy the art - but the image was soon vandalised and drilled into.
The new internal damage is somewhat of a mystery though as no one is currently living in the property.
Kaveh added: "It's difficult to say how they got in. There was no burglary, let's put it like that.
"Someone had a key I'm guessing. There was no broken windows or forced entry."
- Daily Mail