How am I supposed to get a property release for an illegal mural?

You will have to track down the artist. If they’ve signed the piece, you might have some luck via Google. If you’re unable to track down the artist and have a release signed, unfortunately, we are unlikely to accept the asset. Legal or not, street art counts as protectable art. The legal position regarding street art and graffiti is a changing one, and while there remain some instances where we will be able to accept unreleased street art, increasingly, we cannot.