Police caught a group of 18 trespassers and arrested four people at the south Puget Sound area high school after Sonitrol Pacific detected them August 1.
Operator Joe Orsborn received an impact-activated audio alert from the school just after midnight and called the school district’s security guard service to investigate.
The security guard found 18 people outside the school. Tacoma Police were called to arrest four.
No one went inside the school.