A stencil by Cartrain, the 17-year-old graffiti artist who was arrested for stealing a box of pencils from a Damien Hirst installation at the Tate Britain

Cartrain, the 17-year-old graffiti artist who tangled with Damien Hirst last year, is in trouble again, and this time it’s brought him criminal charges.

Last winter the teenager was forced to forfeit £200 ($284) in profit to Hirst after the art-world superstar threatened to sue him over the use of an image of his $100 million diamond-encrusted skull, For the Love of God. Cartrain was also ordered by the Design and Artists Copyright Society to hand over his collages based on the skull. To retaliate, this past July he visited Hirst's installation Pharmacy at the Tate Britain, removed a box of pencils from the artwork, and then created a mock “wanted” poster saying he would return the pencils if the DACS gave him his collages back. The stunt backfired badly when police arrested the teen, informing him that the pencils were worth £500,000 as part of the overall installation, which is valued at £10 million. Cartrain is now out on bail until Sept. 11. If he’s convicted, the case will be the highest-value theft of modern art in Britain.