Well, if the police don't know who Banksy is, and there's no evidence that his "inner circle" is aiding his crimes, what can they do? Then again, I know almost

Well, if the police don't know who Banksy is, and there's no evidence that his "inner circle" is aiding his crimes, what can they do? Then again, I know almost nothing about UK criminal law, so I don't know the limits and requirements for compelling someone to give information.