PHOENIX -- About half the student population at Carl Hayden High School turned up for classes Friday, after a note found on campus earlier in the week threatened violence on Valentine's Day.
Security was increased, with backpacks, large purses and even stuffed animals banned from campus for the day. The note said there would be a shooting.
"We take threats very seriously, even those that come before the start of a three-day weekend. This is just the nature of our business," said Craig Pletenik, a spokesman for Phoenix Unified School District.
About 2,000 students attend the school, near 35th Avenue and Roosevelt Street.
Phoenix Police stepped up patrols in the area.
Students who reached campus with the banned items had them taken away. The items were to be returned at the end of the day.