Editor's Note: Waukesha police are expected to provide an update at 1 p.m. Monday, Nov. 22. Here's the latest. Our original story continues below.
A joyous scene of marching bands and children dancing in Santa hats and waving pompoms turned deadly in an instant, as an SUV sped through barricades and into a Christmas parade in suburban Milwaukee, killing at least five people and injuring more than 40 others.
A “person of interest” was in custody, Waukesha Police Chief Daniel Thompson said, but he gave no details about the person or any possible motive. The investigation was ongoing, with assistance from the Wisconsin Department of Justice.
The city of Waukesha posted on its social media accounts late Sunday that it could confirm at least five died and more than 40 were injured, while noting that it was still collecting information and those numbers could change. The city's statement also noted that many people took themselves to hospitals. The city did not release any additional information about those who died.
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While the investigation was in its early stages Monday morning, five sources in a position to be briefed told NBC News there has been no connection made to terrorism. They also said at the current early stage the incident did not seem to be retaliation around the Kyle Rittenhouse trial, in which the jury returned a verdict on Friday clearing him of charges.
Sunday's holiday parade was live-streamed on Facebook, and a portion of the video showed a red SUV driving through the parade at what appeared to be a high rate of speed followed by gasps and sirens.
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“What took place in Waukesha today is sickening, and I have every confidence that those responsible will be brought to justice,” Attorney General Josh Kaul, the state’s top law enforcement officer, tweeted.
The incident may have transpired when a knife fight or stabbing occurred and then the person of interest in custody fled, according to four senior law enforcement officials who spoke to NBC News. They added this person may have a significant criminal history.
Police aren't looking for anyone else in connection with the vehicle incident, but may be seeking additional suspects in the knife fight, the sources said.
At approximately 4:39 p.m. CT, an SUV went through a barricade at Gasper Avenue and Main Street and then proceeded to drive into the crowd that gathered for the parade, Thompson said.
One video shows the SUV striking what appears to be members of a marching band and several others along the parade route before driving on. The sound of the marching band heard before the SUV approaches is replaced by screams.
Police said at one point an officer discharged their gun, firing shots at the suspect's vehicle in an attempt to stop it. No bystanders were injured by the gunfire, and Thompson said he did not know if the driver was struck by the officer’s bullets. They do not believe any shots were fired from inside the car.
The scene was said to be safe and secure in the hours following the incident, police said at an 8 p.m. news conference.
Main Street will remain closed from Barstow and Main to Wisconsin and Main until at least midday on Monday, the city said, and businesses in this area should remain closed.
The city said that once the area is reopened, space for a temporary memorial will be made at Veterans Park.
"The community mourns the loss of our community members and those injured," the statement from Waukesha said. "We are asking for the community to come together during this time and to keep the families in your prayers."
Earlier in the evening, a pair of hospitals had reported treating 28 people, while police and local hospitals said at least 11 adults and 15 children were injured. Information about the severity of injuries wasn't immediately known, authorities said. "Some" fatalities were reported at the time, but police declined to provide a number of those who died, citing privacy of the victims' families.
As of 8 p.m., Children's Hospital of Wisconsin said it received 15 patients from the incident, with no fatalities reported at the time.
Aurora Medical Center in Summit was treating a total of 13 patients late Sunday: three in critical condition, four in serious condition and six in fair condition, according to a statement.
The Roman Catholic Archdiocese of Milwaukee said one of its priests, as well as multiple parishioners and Waukesha Catholic school children, were injured in the incident.
Angelito Tenorio, a West Allis alderman who is running for Wisconsin state treasurer, told The Associated Press that he was watching the parade with his family when they saw the SUV come speeding into the area.
“Then we heard a loud bang,” Tenorio said. “And after that, we just heard deafening cries and screams from the crowd, from the people at the parade. And people started rushing, running away with tears in their eyes crying.”
Tenorio said he saw about 10 people, children and adults, on the ground who appeared to have been hit by the vehicle.
“It just happened so fast,” he said. “It was pretty horrifying.”
The Waukesha school district canceled classes Monday, stating that they will have "additional counselors available" for students and staff.
The city also advised anyone who may need to talk with someone about the experience of the scene to call 211.
An FBI spokesperson said its Milwaukee field office was aware of the incident and that local and state authorities were leading the response. The White House is also monitoring the situation, according to a statement.
On Twitter, Wisconsin Governor Tony Evers said that he and his wife are “praying for Waukesha tonight and all the kids, families, and community members affected by this senseless act.”
The parade is sponsored by the city’s Chamber of Commerce. This year’s edition was the 59th of the event that’s held each year the Sunday before Thanksgiving.
Waukesha is a western suburb of Milwaukee, and about 55 miles (90 kilometers) north of Kenosha, where Kyle Rittenhouse was acquitted Friday of charges stemming from the shooting of three men during unrest in that city in August 2020.