The teenage girl who shot dead a teacher and another pupil on Monday had a disturbing obsession with other school shooters, it is reported.

Pictures have emerged of Natalie Rupnow, also known as Samantha, wearing a T-shirt of Columbine killer Eric Harris's favourite band KMFDM. A further image posted on her dad's Facebook page captures Rupnow, 15, aiming a rifle at a shooting range as she dons the merchandise of KMFDM, a German hard rock group.

Eerily, Harris was seen in photos also wearing one of the band’s T-shirts before he and Dylan Klebold went on to murder 13 people in the 1999 Columbine High School massacre in Colorado. The band’s acronym name loosely translates to "no pity for the majority."

And, as with Harris and Klebold, Rupnow turned the gun on herself and died of a self-inflicted gunshot wound after her rampage, which killed another teenage student and teacher at the Abundant Life Christian School in Madison, Wisconsin on Monday.

But police say they are still working to uncover the teenager's exact motives for the horror, which has also left two other people with life-threatening injuries. It is is unclear if these people are children or adults.

Rupnow poses with a rifle in a picture which has emerged on social media (
Image:
Facebook)
Madison Police Chief Shon Barnes speaks to the media

A CashApp account reportedly linked to Rupnow features a picture of the Columbine shooters. Her father, asked by a Facebook user if that was "Kiddo" in his shooting-range snapshot, replied, “sure is!!!!... We joined NBSC this spring and we have been loving all every second of it!" Other photos on Rupnow’s dad’s Facebook page show her happily romping in the leaves with two dogs.

Following Monday's tragedy, Vice President Kamala Harris said: "Our nation mourns for those who were killed and we pray for the recovery of those who were injured. Solutions are in hand. But we need elected leaders to have the courage to step up and do the right thing."

A memorial near the school honours the victims of the attack. Mackenzie Truitt, 24, placed a red poinsettia plant at the memorial, as her brother had left the school last year.

She said: "My heart sunk because I know how awesome a lot of these kids are. I know how scared everybody was. Couldn’t get a hold of certain people. Just really scary having to deal with that. It’s sad how often these are happening and how mental health is declining and it doesn’t seem like there’s anything anybody can do to stop it."