Parents in Chattanooga, Tenn., are still trying to make sense of the tragedy that struck their community Monday when a school bus with 35 children aboard struck a tree, killing five and injuring nearly two dozen more.

The driver, Johnthony Walker, 24, was arrested and charged with five counts of vehicular homicide, reckless endangerment and reckless driving for the crash on the winding road.

As the city mourns, chilling reports have emerged alleging that Walker asked the students, “Are y’all ready to die?” before swerving off the road into a tree.

Jasmine Mateen, the mother of three children aboard the bus, lost her 6-year-old daughter in the crash. She told CBS News what one of her other children had to say about the driver.

“My daughter said right before the bus flipped that he was speeding around the curve and asked them ‘Are y’all ready to die?’” Mateen said to CBS correspondent Mark Strassmann.

Booking photo of Johnthony Walker, driver of the school bus. (Photo: Chattanooga Police Department)

She also said she had complained about Walker’s behavior many times since August, but nothing had been done to redress her grievances. The private bus company involved has had 36 crashes with injuries in Tennessee alone since 2014, the Tennessean newspaper reported.

Authorities have not confirmed Mateen’s statements.

Chattanooga Police Chief Fred Fletcher said at a press conference late Monday that the type of accident to which his department and others were responding is “every public safety professional’s worst nightmare.”

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“As bad as it is for the police officers, firefighters and paramedics working that crash and that investigation, we can’t even begin to imagine how much worse it is for the families, the friends, the loved ones of the victims. All of our hearts go out to them,” he said.

A school bus is carried away Tuesday, Nov. 22, 2016, in Chattanooga, Tenn, from the site where it crashed Monday, Nov. 21. (Photo: Mark Humphrey/AP)

According to Fletcher, the Chattanooga Police Department received a call just after 3:30 p.m. asking it to respond to a school bus crash involving students from Woodmore Elementary School, ranging from kindergarten to fifth grade.

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“This is an absolute nightmare for this community, for this police department and for our partners in fire and EMS,” Fletcher said. “But I can assure you that the public safety professionals in Chattanooga are prepared and trained to make sure this is investigated thoroughly.”

He said a warrant had been issued to remove the black box from the bus and to remove the video evidence for inspection.

Twenty-three students were taken to area hospitals, and 12 were still there as of Tuesday evening, with six in critical condition.

“Many of them were scared or too dazed to talk to us,” Dr. Darvey Koller of the Children’s Hospital at Erlanger said at a Tuesday news conference.

Police say Walker was driving well above the narrow road’s 30 mph speed limit at the time of the crash. The incident has revived a debate about whether there should be a federal law requiring school buses to be equipped with seat belts.