Guman Dylan Butler was a student at the rural Iowa high school where cops said he killed at least one and injured five others in a Thursday morning attack.

The 17-year-old was armed with two firearms and a makeshift explosive device when he opened fire at Perry High School at 7:47 a.m., police said.

A sixth-grader was killed and five others injured, one of whom is reportedly the school’s principal.

Butler turned the gun on himself before police could find him, cops said.

He was found with the not-yet detonated improvised explosive device, which cops described as “rudimentary.”

The teenager is believed to have acted alone, though his motive remains unclear.

He reportedly posted a cryptic video to his since-deleted social media in the moments before the harrowing rampage at the small town campus that housed both a middle school and high school, 40 miles northwest of Des Moines.

The attack came on the first day back in class after winter break, but Butler opened fire before the opening bell when “very few students and faculty” were in the building, Dallas County Sheriff Adam Infante said at a press conference in the aftermath of the shooting.

This is a developing story. Check back for updates.