We're getting a look at what this 16-year-old girl told officers after she was arrested, before she could carry out her threat at Red Mountain High School.
ABC 15 is not revealing the identity of the girl because she is underage.
Just days after the elementary school shooting massacre in Connecticut, the girl posted a violent comment on YouTube that said, "I now literally have a plan of seriously hurting... Killing... Murdering people in my high school."
In the interrogation, she also goes into detail about how simple it would be to attack her school.
Police arrested her at her parents' home where there were guns. The girl's mother and father told detectives their daughter did not have access to the weapons, but during the interrogation, the girl said if she got her hands on them, "she was afraid she would use them to hurt herself and others."
"Sometimes I'm rational and like, 'why would I ever do that?' Then I'm like irrational and just want to frickin' kill everyone," she told an officer.
The girl, who identifies herself as transgender, said she was angry at everyone and everything. The threat she originally posted was on a popular transgender section of YouTube.
After her parents left her in juvenile detention for weeks, the Mesa 16-year-old is back in her parents' care. She is currently suspended from school and has been ordered to wear an ankle monitoring bracelet until her next court date.