9 AM Monday morning. A report lands on your desk: Jeanette‘s monogrammed silver locket has gone missing. The last time she definitely remembers having it, she was walking in the Field with her friend Susan. Shifty hallmate Ashley had also been admiring the locket recently.
Do you:

Drag Ashley in for interrogation?
Comb the Field for clues?
Try to stimulate Jeanette‘s memory?
Put Susan under surveillance?

Solve the case quickly, and everyone will applaud your leadership. Be too heavy-handed in your approach, and public opinion will turn against you. Let a thief slip through your fingers to strike again, and the whole school’s reputation will suffer.