Pictured is the baby-faced killer who shot a classmate and a teacher at her high school in Wisconsin.

Natalie Samantha Rupnow, 15, killed herself after carrying out the massacre in a study hall at Abundant Life Christian School. She also injured six other people, including two students who were in critical condition.

A substitute teacher and three students were taken to hospital with less serious injuries, and two of them were released by Monday evening.

Rupnow’s father, Jeff Rupnow, has shared several pictures of his daughter over the years – leading up to her birth in 2009.

The father is working with the police to find a motive for the tragedy.

The shooter’s divorced parents shared custody of their child, but the shooter lived primarily with her 42-year-old father, according to court documents.

Investigators are focusing Tuesday on determining the motive for the school shooting that left a teacher and a student dead and two other children in critical condition.

Madison Police Chief Shon Barnes said investigators were aware of a “manifesto, if you want to call it that, or some sort of letter” from someone who may have known the shooter, 15-year-old student Natalie Rupnow.

“We haven’t been able to find this person yet, but we’ll be working on that today,” Barnes told CNN.

“We will also be looking through (Rupnow’s) possessions, whether she had a computer or a cell phone, to see if there are any transmissions between her and anyone else, and that will give us an idea of ​​what kind of planning.”

Chief Barnes said they are trying to put together a timeline of the shooter’s final hours before she left for school.

Barnes said they have asked the ATF to expedite the investigation into the origin of the weapon used in the shooting and how the 15-year-old came into its hands. He said he wasn’t sure if the gun belonged to her parents or was owned by them.

When asked whether their parents could be charged with a crime, Barnes said they had volunteered information, but he also wanted to consider whether the parents had acted negligently. But at this point, he said that doesn’t appear to be the case.

In recent years, there have been two high-profile cases in Michigan and Georgia in which parents were prosecuted after their children were charged in school shootings.

Jeff Rupnow posted a picture on Facebook showing his daughter at a shooting range. A friend asked him if it was his daughter in the picture. He replied: “I joined the NBSC (North Bristol Shooting Club) this spring and we have loved every second of it.”

The NBSC — or North Bristol Sportsman’s Club — is a gun club in the Madison suburb of Sun Prairie that offers annual family memberships for just $90, according to its website.

The association was founded in 1970 and has more than 600 members. The Rupnows’ alleged membership has not yet been confirmed by the club. DailyMail.com has contacted the NBSC for comment.

Abundant Life is a nondenominational Christian school – pre-K through high school – with approximately 420 students in Madison, the state capital.

The school does not have metal detectors but uses other security measures, including cameras.

Children and families were reunited at a health clinic about a mile away. Parents hugged their children to their chests while others squeezed hands and shoulders as they walked side by side. A girl was comforted with an adult-sized coat around her shoulders as she walked to a parking lot full of police vehicles.

The school shooting was the latest of dozens in recent years across the U.S., including particularly deadly ones in Newtown, Connecticut; Parkland, Fla.; and Uvalde, Texas.

Guns were the leading cause of death among children in 2020 and 2021, according to KFF, a nonprofit organization that addresses health care issues.