Angela O’Boyle was watching the Christmas parade in Waukesha, Wisconsin, from her balcony when a red SUV sped through the crowd and ran into a marching band. O’Boyle described the event, which ultimately resulted in the death of five people and more than 40 injured, as "surreal."

"I saw the red truck crash into the band members," O’Boyle said Monday on "Fox & Friends."

WAUKESHA CHRISTMAS PARADE: 5 DEAD, 40 INJURED AFTER SUV PLOWS THROUGUH WISCONSIN CROWD: LIVE UPDATES

"He continued all the way down the block to the end of the street. Didn’t stop at all. Just kept going and running over people the entire time."

Waukesha had canceled the Christmas parade in 2020 due to the COVID-19 pandemic. O’Boyle said this was the first year she was able to watch the parade from her balcony.

A police car is seen at Main Street in downtown Waukesha, as it's blocked off after a car plowed through a holiday parade in Waukesha, Wisconsin, U.S., November 22, 2021.  REUTERS/Cheney Orr

A police car is seen at Main Street in downtown Waukesha, as it's blocked off after a car plowed through a holiday parade in Waukesha, Wisconsin, U.S., November 22, 2021.  REUTERS/Cheney Orr

She was recording a video of the parade to show her children when she ended up documenting the horrific moment the car drove into a crowd.

"I couldn’t believe it was happening," she said.

Waukesha police confirmed that the person of interest is in custody and has been identified as Darrell Brooks Jr., a Milwaukee man with a criminal history dating back to 1999 that includes numerous violent felonies.

Multiple senior law enforcement sources told Fox News that the 39-year-old longtime felon was being questioned in connection with the attack.

WAUKESHA CHRISTMAS PARADE HORROR: WISCONSIN POLICE UNTION OFFICIAL REVEALS WHATS'S NEXT IN INVESTIGATION

Jordan Woynilko, who also witnessed the incident, told Fox News digital that he watched as the SUV struck nearly two dozen people. 

"There were moms and dads yelling for their kids, people running around," he said. 

O’Boyle said bystanders and those watching the parade immediately took action after the car ran through the crowds. 

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"It was instant that they moved into the people that were injured," she said.

"Instantly, everyone was running towards them or grabbing children and putting them inside buildings that were right away. People jumped quickly into action."

Fox News' Michael Ruiz contributed to this report.