Police in Madison are trying to determine what prompted a 15-year-old student to open fire at a private Christian school. The shooting on Dec. 16 was just days before the winter break. A fellow student and a teacher were killed. The shooter also died.

Here are some things to know about the shooting.

What happened in Madison?

Gunfire erupted late in the morning of Dec. 16 at Abundant Life Christian School in Wisconsin’s capital city. Police said that a second grade teacher called 911 to report the shooting. Authorities had earlier reported that the caller was a student.

Police Chief Shon Barnes said Natalie Rupnow, who went by the name Samantha, opened fire during a study hall, killing another student and a teacher, and wounding six others.

The teacher and student were pronounced dead at the school, he said. Their names have not yet been released. Two students remained in critical condition on Dec. 17, police said. A teacher and three students were taken to a hospital with less serious injuries, and two of them had been released by the evening of Dec. 16.

Rupnow also died, likely by suicide, Barnes said. Police officers did not fire their weapons, he said.

Investigators believe the shooter used a 9 mm pistol, a law enforcement official told The Associated Press. The official spoke on the condition of anonymity because they were not authorized to discuss the ongoing investigation.

The school website shows that Dec. 20 was to be the last day before the holiday break.

President Joe Biden, in a statement, called the shooting “shocking and unconscionable,” and urged Congress to act immediately.

“Every child deserves to feel safe in their classroom,” Biden said. “Students across our country should be learning how to read and write — not having to learn how to duck and cover.”

Why did the shooter do it?

Police are trying to determine what led to the shooting. Barnes said officers were talking with Rupnow’s father and other family members, who were cooperating, and searching the shooter’s home.

A “combination of factors” motivated the shooting, Barnes said Dec. 17, but he declined to specify what they were. Investigators are asking students about whether bullying was an issue, Barnes said.

Barnes said it doesn’t appear the victims were targeted in the shooting. He said “everyone was targeted.”

Speaking on CNN, Barnes said police are trying to put together a timeline of the shooter’s last hours before she went to the school.

Barnes said they’ve asked the ATF to expedite their investigation into where and how the 15-year-old got the gun. He said he’s not certain if the weapon was owned or possessed by her parents.

What is known about the school?

Abundant Life Christian School is nondenominational and has about 420 students from pre-kindergarten through 12th grade, according to Barbara Wiers, campus director of elementary and school relations.

She said at a news briefing on the afternoon of Dec. 16 that the school does not have metal detectors but uses other security measures including cameras. She also said guns are not allowed on campus and that the school regularly practices safety routines.

“When they heard ‘lockdown, lockdown,’ they knew it was real,” she said.

Wiers said just before the school year, they had done a retraining with the Madison Police Department, so it was “very fresh for faculty.”

A candlelight vigil is planned for the night of Dec. 17 at the Wisconsin State Capitol.

The school’s website said it was founded in 1978 “to offer students academic excellence in a Christ-focused context.” The website said the school is accredited through the Association of Christian Schools International.

Have religious schools been targeted elsewhere?

Less than two weeks earlier, a gunman critically wounded two kindergartners at a tiny religious school in Northern California and then killed himself. Butte County Sheriff Kory L. Honea said Glenn Litton was mentally ill and believed that by targeting children on Dec. 4 that he was carrying out “counter-measures” in response to America’s involvement in Middle East violence.

Litton, 56, got into the Feather River School of Seventh-Day Adventists in Oroville, California, by pretending he wanted to enroll a fictitious grandson, Honea said. He used a handgun to shoot and critically wound the boys, ages 5 and 6. Authorities said Litton was found dead afterward near the school’s playground.

How many school shootings have happened in 2024?

The website for the anti-violence organization Everytown for Gun Safety shows that there have been at least 202 incidents of gunfire on school grounds, resulting in 56 deaths and 147 injuries, in 2024. That data doesn’t include the Madison shooting.

The deadliest school shooting in 2024 happened in September at Apalachee High School in Georgia. Authorities said 14-year-old student Colt Gray opened fire with a semiautomatic assault-style rifle. Four people were killed and nine more were hurt, seven of them shot. A grand jury subsequently indicted Gray and his father Colin Gray — who was accused of giving his son access to the gun — on murder and other charges. Both have pleaded not guilty.

In 2023, 45 people died in 158 school shootings, the Everytown for Gun Safety website shows. Sixty-seven people died in 181 school shootings in 2022, according to the data.

School shootings in recent years, including deadly ones in Newtown, Connecticut, Parkland, Florida, and Uvalde, Texas, have set off fervent debates about gun control and frayed the nerves of parents whose children are growing up accustomed to doing active shooter drills in their classrooms. But school shootings have done little to move the needle on national gun laws.