Phoenix police have identified the 16-year-old Maryvale High School student who was fatally stabbed by a classmate on Tuesday.
Phoenix police say Michael Montoya II was attacked in class by another student armed with a folding pocket knife.
No motive has been revealed.
The Phoenix Union High School District did not immediately answer whether Maryvale High School has metal detectors.
The teenage suspect is in custody but has not been identified. Investigators say he ran out of the classroom, dropped the knife and was detained by security who saw his hand bleeding.
Roughly 2,700 students are enrolled at Maryvale High School, according to U.S. News and World Report.
Class schedules at Maryvale High School were changed Wednesday so students can receive grief counseling after a classmate was stabbed to death on campus Tuesday.
