Authorities say a 16-year-old girl from Mesa was arrested Thursday after she posted a threat on YouTube that she had a plan to kill people at her high school and then commit suicide.
"I now literally have a plan of seriously hurting… killing… murdering people in my high school. And a playlist to do it" part of the post read.
It was posted 3 days ago. The owner of that transgender YouTube channel alerted police in Toronto, who then called the sheriff's office.
The Maricopa County Sheriff Office says the girl had access to guns at her home, but never brought firearms to Red Mountain High School in Mesa.
The agency says investigators arrested the girl at her home Thursday morning and that she admitted to posting the threat.
According to the sheriff's office, when she posted the comment three days ago, she had serious thoughts and even plans to shoot people and bomb the school. She told deputies she had been planning this in her head before last week's massacre in Connecticut.
She told investigators she even thought about cutting the wires on the security carts on campus in order to slow the response.
The girl's parents are being cooperative and admitted to having a few guns in the home.
"You talk about a high school. The access the 16-year-old had, pre-meditation, planning to do something awful so we are just happy and we feel that we did prevention here," said Sheriff Joe Arpaio.
"She was talking about a bomb and she knew all the areas of the high school. She wasn't a stranger. She went to the high school, where the fence was, what it would take... I don't know what more you need for probable cause," Arpaio said.
"With the social media the way it is, it's easy to get your emotions out there. Kids are not really concerned about what they say it seems like," said local parent Joe Langlais.
Red Mountain High School was in session Thursday, but they have early release Thursday and Friday. There will be an extra security presence on Friday.
The 16-year-old has been booked into the juvenile detention system. A motive isn't clear, and deputies say the teen made no mention of bullying.
"If this went along without any detection or intervention, who knows, two years from now, one year from now or next week what would snap in that young person's mind to commit these type of acts," added Arpaio.
Statement by Mesa Public Schools
Overnight, a Red Mountain High School student was taken into custody by the Maricopa County Sheriff's Office, based on an online post that indicated this student intended to harm herself and people at the school.
At this time, we do not believe the school was in imminent danger.
We are grateful to the Toronto, Canada, police department for its swift actions in uncovering and investigating the situation, and the sheriff's office for its follow up.
Student and staff safety continues to be our No. 1 priority. The school will conduct final exams as scheduled tomorrow, with an increased presence of security on the campus.
The Associated Press contributed to this report.