Plot: a sophisticated killer kills a teacher but wants to pin it on a student in her class, because he's seen them together. Killer wants to mislead the police in believing teenager did it. Teenager parents are successful bakers. Teenager is thus affluent (has car) My possible way in: Killer plants evidence of crime (knife and victim's underwear) in bakery delivery van then calls police (anonymously) to report crime Killer jumps fence after crime into teenager parents' home and plants evidence The problem I am having: the police needs to find evidence while interviewing teenager and parents and take teenager away as murder suspect (which the killer wanted all along) The help I need: how can the police find the evidence? can they find this just by interviewing the teenager since he was one of the last to see the teacher alive? Thanks for the help!