The pre-Christmas buzz and serene sense of safety at a Wisconsin private school were shattered when a student pulled out a gun and opened fire – killing two people, wounding six others and devastating a bewildered community.

Now, investigators are digging into how and why the 15-year-old shooter, identified as Natalie Rupnow, got the gun used to unleash terror at Abundant Life Christian School – traumatizing some 420 students from kindergarten to 12th grade.

Madison Police Chief Shon Barnes said Tuesday the motive for the shooting appears to have been a “combination of factors,” but declined to give more details.

“Some have asked if people were specifically targeted. Everyone was targeted in this incident, and everyone was put in equal danger,” he said.

The police chief previously told CNN that authorities are also investigating whether the shooter’s parents owned the gun.

“We also want to look at if the parents may have been negligent. And that’s a question that we’ll have to answer with our district attorney’s office,” Barnes said. “But at this time, that does not appear to be the case.”

Madison police are also working with the Bureau of Alcohol, Tobacco, Firearms and Explosives to find the origin of the gun.

“We have asked our partners with the ATF to expedite what’s called an ATF trace form to try and determine the origin of that weapon, who purchased it and how it got from a manufacturer all the way to the hands of a 15-year-old girl,” Barnes said. “These are questions that are going to take some time to answer.”

The motive might also take time to determine. The shooter, who also went by the name Samantha, died of a self-inflicted gunshot wound, police said.

Investigators are looking into online posts and a possible manifesto that might be linked to the shooter, the police chief said Tuesday.

“We have been made aware of a manifesto, if you want to call it that, or some type of letter that’s been posted by someone who alleged to be her friend. We haven’t been able to locate that person yet, but that’s something we’re going to work on today,” Barnes said.

“We’ll also be looking through her effects – if she had a computer or cell phone – to see if there are any transmissions between her and someone else.”

The tragedy marks the 83rd school shooting across the United States this year – surpassing 2023 for the most school shootings in a single year since CNN began tracking such incidents in 2008.

‘I don’t think they’ll be OK for a long time’

Excitement filled the air when children filed into the school Monday morning. It was the last week of school before Christmas break, and students had a week full of festivities to look forward to – including a holiday concert and an Ugly Christmas Sweater Day, according to the school’s website.

Like the other students, the shooter entered Abundant Life at the beginning of the school day. Shortly before 11 a.m., she was inside a study hall classroom with students from mixed grades when she pulled out a handgun and opened fire at her peers, police said.

The shooter killed a student and a teacher, police said. Their names have not been publicly released, as authorities wanted to make sure family members were notified first.

Six other people were taken to area hospitals, the city of Madison said. “Two students remain in critical condition and have life-threatening injuries,” the city said Tuesday morning.

At least two patients were in stable condition Tuesday morning at SSM Health St. Mary’s Hospital, and two had been released, a hospital spokesperson said.

Survivors of the attack – some as young as 7 or 8 – recalled screaming in the hallways of the school, saying they were “really scared” and “really sad,” according to CNN affiliate WISC. Parents anxiously waited to learn what happened to their children.

“Thank God they were safe,” said Mireille Jean-Charles, a mother of three students at the school. “But the trauma – it’s a lot, because I’m sure they lost friends and teachers, which is not OK. And I don’t think they’ll be OK for a long time.”

The police chief said officers are sensitive to the children’s trauma and will not pressure them to help with the investigation – even though many questions remain unanswered.

“We’re not going to interrogate students,” Barnes said. “We’re going to give them an opportunity to come in and speak to what they may have saw when they feel ready, which is why some of these questions can’t be answered.”

The United Way of Dane County announced the creation of the Abundant Life Christian School Emergency and Recovery Fund, which the non-profit said will raise funds to support children, families and educators affected by the shooting.

Children and medics practiced for this kind of horror

Recent training drills – practiced by students and some of the first responders – may have averted even greater tragedy.

Moments before Monday’s mass shooting, a group of medics from the police department were at a training center 3 miles away from the school rehearsing what to do during a mass trauma incident.

At 10:57 a.m., that nightmare became a reality when a second-grade teacher called 911 to report a school shooting, Barnes said. Previously, Barnes said a second-grade student had called 911 before correcting himself Tuesday.

The police medics “left the training center immediately and came down here – doing in real time what they were actually practicing for,” Barnes said outside the school.

Students at the school were “clearly scared” as the attack unfolded, said Barbara Wiers, director of elementary and school relations for Abundant Life.

But the students were well-trained in active shooter drills and “handled themselves brilliantly,” Wiers said.

Kellen Lewis said his son told him that children huddled in a corner could hear people outside their classroom running and screaming about an active shooter.

“My third-grade son mentioned that his teacher stood between the door and where the kids were, hiding with scissors, ready to do whatever he had to do to defend the kids in that class,” Lewis told CNN’s Jake Tapper.

“The school had prepared them for this sort of a situation. They worked that plan. They did the right thing,” said Lewis, a father of four. “And to reinforce that sense of agency with the kids so that when they remember this, they’re going to remember that they made the right choices. And fortunately for them, it worked out.”

Authorities searched the shooter’s home

Police searched the suspect’s home and were seeking additional search warrants, Barnes said Monday. Rupnow’s father has spoken with police, and the shooter’s parents have not been charged with any crime.

“We have no reason to believe that they have committed a crime at this time,” Barnes said Monday.

Madison Mayor Satya Rhodes-Conway said Tuesday it was “far too early” to comment on whether the teen shooter’s parents will face criminal charges.

“We don’t know nearly enough yet,” Rhodes-Conway said.

But in recent years, some law enforcement agencies have charged the parents of children who opened fire at their schools. The father of 14-year-old Colt Gray, who carried out a mass shooting at Apalachee High School in Georgia, was charged with 29 counts earlier this year.

Both federal and Wisconsin laws generally make it illegal for someone younger than 18 to possess a firearm. According to state law, it’s also illegal for any person to intentionally sell, loan or give a dangerous weapon to someone younger than 18.

But Wisconsin’s state law has exceptions that allow a minor to possess a firearm for target practice under adult supervision, for use in the armed forces or for hunting. In addition, Wisconsin has a child access firearm law that makes it illegal to recklessly store a loaded firearm within reach or easy access of a child younger than 14.

Regardless of how the Madison school shooter obtained her gun, no child should have such access, the police chief said.

“I do not believe that 15-year-olds should have access to weapons that they can bring to school and potentially hurt someone,” Barnes said.

“We really have to do a better job not only in our communities but in our country with making sure that our young folks don’t have access to weapons and firearms and certainly making sure that we’re paying attention to the mental health of our children.”

An ‘unthinkable’ tragedy

A candlelight vigil was scheduled for Tuesday night, with the city’s mayor and education officials expected to attend.

All flags over federal installations and facilities statewide would be lowered to half-staff until December 22 in honor of the victims, Wisconsin Gov. Tony Evers announced.

“As a father, a grandfather, and as governor, it is unthinkable that a kid or an educator might wake up and go to school one morning and never come home,” the governor said. “This should never happen.”

Ending the fall semester how it started

The fall semester is headed into its Christmas holiday break like it began – with a mass shooting.

Rice University in Houston witnessed an apparent murder-suicide on the first day of classes on August 26. The following week, a 14-year-old shooter killed four victims at a high school in Winder, Georgia – making it the deadliest school shooting of the year.

The shooting at Abundant Life also marks the latest shooting to take place at a small, private Christian school – and among the 56 to have taken place on K-12 grounds.

Last year, a shooting at The Covenant School in Nashville left three 9-year-olds and three adults dead.

Earlier this month, two boys, ages 5 and 6, were in critical condition after a shooting at a Christian school north of Sacramento in Oroville, California. The private school, Feather River Adventist School, is affiliated with the Seventh-day Adventist Church, a Protestant Christian denomination.