The Golden State Killer committed at least 13 murders, 50 rapes, and 120 burglaries during the 70s and 80s, and eluded law enforcement for 32 years. On April 24, 2018, Joseph DeAngelo was arrested. But what tips the scales and makes the difference in finally solving these types of cases? Phelps unpacks the science with DNA specialist and Forensic Scientist Dr. Claire Glynn, a leading expert in forensic genetic genealogy, discussing how this crime-solving tool actually works.