A thin blue line patch is stitched onto the uniform of a Mount Prospect sergeant as he guards the entrance to the village hall before a meeting of the village board to vote on the patch Aug.... 6 storming of the U.S. Capitol, among other events.... Both sides have taken offense and claimed that the other’s characterization of the patch was a “ slap in the face.” Chief James Koziol said many people buying the patches have been officers from other departments, including Chicago.“ The outpouring