It was a crime that rocked an idyllic seaside town in Cape Cod -- the 2002 murder of Christa Worthington, found stabbed to death with her 2-year-old daughter, unharmed at her side. What came next was a three-year search for her killer that would involve unorthodox steps by police, a lengthy list of potential suspects, and an entire town under suspicion. Christa's trash collector, Christopher McCowen, would eventually be convicted of the crime, but his trial would raise questions about the evidence, investigative methods, and whether racial prejudice played a role. Now, ABC Radio and "20/20"...