A US man pleaded guilty to defacing two murals in Park City, Utah, the US, believed to have been done by the mysterious British graffiti artist Banksy.

If David William Noll, 36, pays €10,000 in restoration costs before a November sentencing hearing, prosecutors say they will not seek jail time as part of a plea deal.

Noll told a judge he was suffering from a bout with bipolar disorder when he drove to Park City and damaged the works on New Year’s Eve.

Banksy is a pseudonym for the graffiti artist known for silhouetted figures and spray-painted messages that show up in unexpected places.His works have sold for as much as €840,000 at auction.

The Park City murals appeared on the city’s historic Main Street in 2010, around the time Banksy was in town for the Sundance Film Festival debut of his documentary, Exit Through the Gift Shop.

One depicts a young boy with a pink halo and angel wings kneeling to pray behind a can of pink paint. It was found covered in brown spray paint after the protective glass was shattered. Also damaged was a bulletproof glass cover over a mural of a cameraman shooting video footage of a flower.

Citing You Tube videos police say Noll posted about the vandalism, Summit County attorney David Brickey said he appears to be a frustrated artist who did not understand the acclaim surrounding the elusive Banksy.