It was supposed to be a celebratory night in Waukesha. Dance groups and high school bands and politicians were marching along Main Street in the Milwaukee suburb’s Christmas parade, which was returning from a pandemic hiatus.

Then, just before 4:40 p.m., the driver of a red SUV stormed past barricades and barreled through the crowd, striking dozens. At least five people were killed and 40 people were injured, and the numbers could change, city authorities said in a statement late Sunday. Area hospitals reported treating dozens of patients, including many children. It was unclear what might have motivated the episode.

"Today our community faced horror and tragedy in what should have been a community celebration,” said Mayor Shawn Reilly, who described seeing smiling children and happy parents when he marched along the parade route before the incident. "I’m deeply saddened to know that so many in our community went to a parade but ended up dealing with injury and heartache.”