Natalie Rupnow, the 15-year-old girl police identified as the Wisconsin school shooter who killed a student and a teacher in a deadly rampage, looks like she knew how to handle a firearm ... at least according to the first photos to surface of her online.

In one photo, shared on her father's Facebook page, you see Natalie at a gun range ... and she's shooting a target with a rifle.

Natalie is wearing a shirt featuring the German rock band KMFDM ... which is interesting, because Columbine school shooter Eric Harris was super into the band.

Harris, who shot up Columbine High School in 1999, was photographed in KMFDM shirts before the school shooting ... and he posted lyrics to KMFDM songs "Son of a Gun" and "Stray Bullet" on his website.

Cops in Wisconsin say they do not have a motive here yet ... so it's unclear if Rupnow drew inspiration from the Columbine massacre.

In another photo posted on her dad's FB account, Natalie is seen with two dogs ... and she's hugging one of the pooches in what appears to be a home's backyard.

Rupnow, a pupil at Abundant Life Christian School in Madison, WI, where Monday's shooting took place, injured six others ... including two of whom are in critical condition.

Cops say Rupnow died from a self-inflicted gunshot wound ... another similarity to Harris, the Columbine shooter.