Waukesha city officials say more than 40 people were injured after a vehicle barreled through the crowd. A ‘person of interest’ is in custody.

“This is still a very fluid investigation,” the chief told reporters Sunday night.

Children are among the injured, he said.

It is unknown at this time whether Sunday’s incident was an act of terrorism, Thompson said. “The scene is now safe and secure,” he added.

Aurora Medical Center-Summit, a hospital in Waukesha County, told CNN Sunday night it is treating 13 patients: three listed in critical condition, four in serious condition and six in fair condition. “We are deeply saddened by today’s senseless tragedy and our hearts are with the Waukesha community,” a statement from the hospital said.

Children’s Wisconsin, a pediatric hospital in Milwaukee, said it was treating 15 patients who were hurt, with no reported fatalities as of Sunday night. Waukesha is located about 20 miles west of downtown Milwaukee.

Froedtert Hospital in Milwaukee — the only Level I trauma center in southeast Wisconsin — confirmed to CNN that it is also treating patients but is not providing a specific number nor conditions. Level I trauma centers typically care for the most critically ill patients.

Witnesses describe a joyous night that ended in tragedy

Angela O’Boyle, who lives in an apartment on the fifth floor which overlooks the parade route, told CNN she was on the balcony watching when “the next thing I heard were screams, and turned my head and saw the car come and plow into the band that was just pass my balcony at that point.

“It hit at least two people right away and rolled over them. And then continued down the road to People’s Park which is at the end of the block — and then kept going, it didn’t stop.”

Boyle said she heard screaming and people yelling out their children’s names, adding “it was not something that I wanted to see … a little freaked out.”

Staral went on to say “there were multiple people on the ground.”

In her description into those injured, Staral said “right in front of me in the little spot where I was sitting, probably four people were down, so there were a lot of people that ran to go check on them. I believe that the four people in front of me were still breathing but they were down, they were not moving.”

Schools closed as a community mourns

Roads in the area will remain closed for at least 24 hours, Thompson said. Businesses along roadway where the incident took place should remain closed Monday, city officials said.

Waukesha police had sent a push alert to cell phones in the area after the incident, asking those “within a 1/2 mile radius of the 5 points downtown” to immediately shelter in place. The alert is no longer in effect, Thompson said.

The School District of Waukesha canceled classes on Monday, according to the school district, and will determine if classes will resume Tuesday.

“The District will have additional counselors available during the school day at all buildings for all students that may be in need of support services,” school officials said in a statement.

Waukesha County executive Paul Farrow said he “had just finished participating in the parade with my wife when I noticed police sirens.” Farrow asked for prayers for the community and said he has been in touch with Mayor Shawn Reilly and Gov. Tony Evers.

Waukesha alderman Don Paul Browne told CNN he was marching in the front of the parade and was out before the incident, saying “this is so sad and so senseless.”

The White House is in touch with state and local officials, according to a White House official, and President Joe Biden has been briefed.

“The White House is closely monitoring the situation in Waukesha and our hearts go out to everyone who has been impacted by this terrible incident,” a White House official said. “We have reached out to state and local officials to offer any support and assistance as needed.”