Another Banksy?

A Banksy graffito has recently appeared on the side of the Honeypot building on Upper Maudlin Street in Bristol, the lad's home town. It isn't tagged with Banksy's trademark, but locals reckon it's the real thing. Surely he has enough money by now to employ people to do his graffiti for him. Hey, Banksy, send a team of guerrilla artists to the Kremlin to insult President Putin with graffiti showing Alexander Litvinenko on his deathbed:
"Hi, Vladimir. We all know whodunit."