Has artist Ai Weiwei’s studio been bugged? The dissident artist has been documenting on social media what he believes are listening devices that were hidden in the walls of his building, according to William McLennan in The Independent. Ai had only recently arrived home after being in London last month for the opening of his Royal Academy exhibition, and discovered the alleged surveillance equipment while beginning renovations on his Beijing studio.

Via his Twitter and Instagram feeds, he posted pictures and videos of one device (accompanied by the comment “ha ha”) and then later showed fireworks exploding in a bin next to the device, with the caption: “Can you hear this?”

His trip to London was his first time overseas in four years, after the Chinese government returned his passport three months ago as Artforum.com previously reported here.