Twitter has long been a way for people to keep track of tornado watches, train delays, news alerts or the latest crime warnings from their local police department.  But when the Elon Musk-owned platform started stripping blue verification checkmarks this week from accounts that don’t pay a monthly fee, it left public agencies and other organizations around the world scrambling to figure out a way to show they’re trustworthy and avoid impersonators.

Fake accounts claiming to represent Chicago Mayor Lori Lightfoot, the city’s Department of Transportation and the Illinois Department of Transportation all began sharing messages early Friday falsely claiming that Chicago’s Lake Shore Drive — a major thoroughfare — would close to private traffic starting next month.

A critical eye could spot obvious hints of the fraud. The account handles are slightly different from the authentic ones representing Lightfoot and the transportation agencies. The fakes also had far fewer followers than the legitimate accounts. But the fakes used the same photos, biographical text and home page links as the real ones.