(CNN) — The celebratory sounds of a Wisconsin Christmas parade were interrupted by terrified screams Sunday after a vehicle plowed into participants and spectators gathered for the event in Waukesha, a city about 20 miles west of downtown Milwaukee.

At least five people were killed and more than 40 were injured in the chaos, city officials said.

Here’s what we know about the incident unfolded.

What happened during the parade

Crowds were bundled up along Waukesha’s Main Street to enjoy the parade when a red SUV drove through a series of barricades and barreled onto the parade route around 4:39 p.m. local time, Waukesha Police Chief Daniel Thompson said.

A video of the parade recorded by Angela O’Boyle, who was watching from her fifth-story apartment balcony, shows the SUV hitting an individual in a marching band. The vehicle then continues forward, hitting and running over others in the band and crowd before driving away.

In the video, people can be heard screaming and seen running for safety as the SUV continues its path through the crowd.

Video of the parade published on the city’s Facebook page shows a red SUV driving quickly through the parade, followed by a running police officer.

A Waukesha police officer discharged their weapon in an attempt to stop the driver, Thompson said. No bystanders were struck by the officer’s gunfire, the chief added, noting he doesn’t believe any shots were fired from the SUV.

A vehicle was recovered and a “person of interest” was taken into custody, Thompson said. “The scene is now safe,” the chief said Sunday evening.

Where the investigation stands

Thompson would not say whether the person in custody was the driver of the SUV or if any arrests have been made.

The indications are the Waukesha suspect was fleeing another incident when he drove into the parade route, according to multiple law enforcement sources familiar with the preliminary investigation findings.

While early in the investigation, there is no known connection to international or domestic terrorism, and it does not appear to be connected to the Kenosha verdict, the sources said.

Special Agents with the Bureau of Alcohol, Tobacco, Firearms and Explosives have responded to assist the Waukesha Police Department, according to Erik Longnecker, acting division chief of the Public Affairs Division of the ATF.

Roads in the area will remain closed for at least 24 hours, Thompson said. Businesses along the road where the incident took place should remain closed Monday, city officials said. City Hall is closed to the public, although media will be allowed in for news conferences.

Who was injured

Among the injured are a Catholic priest, multiple parishioners and Waukesha Catholic school children, according to Sandra Peterson, the communication director for the Archdiocese of Milwaukee.

“Please join us in prayer for all those involved, their families, and those who are traumatized from witnessing the horrible scene,” Peterson said in a statement.

The Milwaukee Dancing Grannies posted a statement on Facebook Monday, saying members of the group were among the dead in Sunday’s tragedy in Waukesha, Wisconsin.

“Those who died were extremely passionate Grannies,” according to the group’s statement.

Their statement did not mention how many members of the group were involved in the incident.

Aurora Medical Center-Summit, a hospital in Waukesha County, told CNN Sunday night it was 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.

Froedtert Hospital in Milwaukee — the only Level I trauma center in southeast Wisconsin — confirmed to CNN it is also treating patients but is not providing a specific number or their conditions. Level I trauma centers typically care for the most critically ill patients.

The School District of Waukesha canceled classes Monday, according to the district, and will determine whether 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.

How witnesses described what happened

O’Boyle, who recorded the incident from her balcony, told CNN she was watching the parade 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.”

O’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.”

Angelito Tenorio, who is running for Wisconsin state treasurer and was campaigning at the parade, said the scene was “absolutely chaotic.”

“Nobody knew if this was an attack or if this was an accident or if it was a deliberate attack on the people of the parade,” he said in an interview with CNN. “People just started fleeing, running away from the scene, leaving behind their belongings, grabbing their children, calling, screaming, looking for their loved ones.

“And when the crowd cleared out, that’s when it looked like I saw people, who appeared to be lying in the middle of the street, lying still, lying lifeless.”

Kaylee Staral, a Milwaukee Journal Sentinel intern who also witnessed what happened, told CNN’s Pamela Brown “probably around 20 to 30 minutes into the parade, a red SUV came running down the middle of the street — there were a lot of screams — and we almost thought maybe it was Santa, but it was a red SUV and it hit a lot of people.”

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

In her description of what she saw, 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.”

Governor orders flags flown at half-staff

Wisconsin Governor Tony Evers (D) ordered all flags be flown at half-staff at “all buildings, grounds and military installations” across the state, to honor those who were killed and injured at the Waukesha parade, according to a statement released by the governor’s office Monday.

“While much is still unknown, including the full extent of injuries and the number of lives lost” the statement added, “the people of Wisconsin pray for the Waukesha community and all those affected, and mourn the loss of life that occurred as a result of this senseless tragedy.”

US Sen. Tammy Baldwin (D) of Wisconsin tweeted: The horrific violence at the Waukesha Christmas Parade is just heartbreaking. Please keep the victims in your prayers tonight.”

“My thoughts and prayers for everyone injured in Waukesha’s Christmas parade. My gratitude for all law enforcement, medical personnel, and community members who are responding,” tweeted US Sen. Ron Johnson (R) of Wisconsin.

US Rep. Scott Fitzgerald (R), whose district includes Waukesha, tweeted: “I’m praying for the safety of all those impacted by the senseless tragedy in Waukesha this evening. If you are searching for family, please go to the Waukesha Metro Center, 212 E Saint Paul Ave. I continue to monitor the situation as full details come to light and I’m thankful for all of the first responders who are answering the call for help.”

The-CNN-Wire

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