Natalie ‘Samantha’ Rupnow arrived at Abundant Life Christian School on Monday morning – and just hours later, she opened fire on a study hall, killing two and injuring six others, before turning the gun on herself.

Police identified 15-year-old Rupnow as the shooter at the Madison, Wisconsin-based private school and claimed that the attack had been pre-meditated.

A law enforcement source told CNN that Rupnow ‘had been dealing with problems and expressed some of those in writings, which they are now reviewing.’ A manifesto, that cops have not confirmed is linked to the teen, was published on social media.

The shooter, who went by the name Samantha, was present from the start of the school day and eventually opened fire on a room full of students from various grades, according to Madison Police Chief Shon Barnes.

Cops confirmed that shooter Rupnow was not on their radar and had no prior interactions with her before today, though they said a probe would confirm that.

It was not immediately clear to Barnes or investigators which grade Rupnow attended at the school, which serves students from the age of three to the end of high school.