06/18/2010 11:17 am ET | Updated May 25, 2011

Joe Wilson's Office Vandalized With 'You Lie' Graffiti

An unknown vandal -- or vandals -- defaced a poster and wall in front of Rep. Joe Wilson's (R-S.C.) South Carolina campaign office Wednesday night, writing the very words which made him famous.

When the Wilson for Congress staff came into work on Thursday morning, they found that someone had spray painted "YOU LIE" in large letters in front of the West Columbia office.

"We have no idea who did this," DeRoy told WTOC-TV, but then blamed Democrats.

"It's pretty obvious there's probably a fair amount of 'donkey dung' probably on this incident," he said.

Wilson, who was elected in 2001, made the phrase famous by shouting it at President Obama during a speech to a joint session of Congress last year.

Police are investigating the incident.