What started as a high school sociology project became a real cold-case investigation. Jennifer Fessler sits down with teacher Alex Campbell, whose students spent hundreds of hours digging through evidence, building timelines, challenging theories and chasing answers in the infamous Redhead Murders. Campbell shares what they uncovered, why he believes teenagers are an untapped resource for cold-case investigations, and how their work has now led to a new investigation into a 46-year-old suspicious death.