Fans of the Harry Potter franchise are suspected of vandalising a series of traffic stop signs in the small suburb of Wauwatosa, Milwaukee.
Police have discovered that several signs have had the word 'Voldemort' added in permanent black marker so that they now read 'Stop Voldemort' in reference to the fantasy film's main villain.
"Is it the crime of the century? No. But the problem is it's starting to add up," patrol specialist Paul Liest told the reporters.
It is thought that around 80 signs have been vandalised in the city, although similar markings have also been spotted across the US and in England.
Leist added: "You couldn't find a more important sign to vandalise. It's imperative people can read a stop sign. We'd like to see this come to an end. Besides we've got more important things to attend to."
Speaking to the Chicago Tribune, Captain Jeff Sutter admitted that officers had only realised what the vandalism meant when one policeman's young son came forward to enlighten them.
"It took a seven-year old to tell us what [the graffiti] was," he explained. "We thought it was just some type of new tagger."
Residents have been offered cash rewards for any tips that lead to an arrest. It is estimated that each sign will cost $80 to replace.