LEHI, Utah — Lehi Police arrested an 18-year-old Skyridge High School student after they said he threatened to “shoot up his school” during a therapy session.

According to a probable-cause statement, the student was talking with a therapist Thursday afternoon when he began to discuss violence.

“[He] ‘unloaded’ on [the therapist] for approximately 45 minutes, disclosing his desire of shooting up his school and murdering a person that hurt his friend. [He] would not disclose names, when he would carry out his plan(s), or details of the plans. He only explained that he fantasizes over these murderous thoughts constantly and he spent 3+ hours last night (3/13/19) planning it out,” the probable-cause statement said.

The therapist told police she did not believe the student planned to act imminently, but was alarmed enough to alert them.

Police sent officers to the school, where a function was taking place. After pinging the student’s phone, they discovered him at his home with his family.

Police said the student agreed to speak privately with them.

“Detective Prawitt asked [the student] to tell us everything that was discussed with [the therapist] and why he thought that would warrant a response of police to his home. [The student] agreed and opened up, releasing frustration, odd responses, and several bone-chilling responses to our questions. After speaking with [the student], all officers on scene felt the next step of [his] plan… was execution. Execution on Skyridge high school and specific people,” the probable-cause statement said.

Police arrested the student for investigation of threat of terrorism.

Lehi Police Sergeant Damon Faught said police must act when threats are reported.

“It is tough because you’re not sure whether he was intending to do it or whether this was just stuff that he was thinking about, but anytime we get a threat like that, we have to take it serious. We would rather investigate it and have it turn into nothing than to not be aware of it and have it turn into a catastrophe,” Faught said.

Skyridge High School Principal Dr. Joel Perkins emailed parents at the school Friday morning informing them of the situation.

“Our students, faculty, and staff are all safe. We are so grateful to the Lehi Police Department for their quick resolution of the situation and for their professionalism in helping ensure the safety of our school community. We appreciate that someone saw something and said something. We love the Skyridge community and your kids!” Perkins wrote.

Faught said he hoped people recognized the importance of reporting things that concerned them.

“If you hear or see something, make sure you say something. That way we can get involved. That’s what worked out so well last night is we were able to intervene as quickly as we could. We worked with the school district. The school district was able to get their information out to the people that they needed to get it out to. We were in contact with them last night and met with them first thing this morning and we had an officer at the school all day today to make sure everything was fine,” he said.