How a dogged detective cracked a quadruple-murder cold case and revealed a suspected serial killer

In an exclusive interview with CNN, a Texas cold case detective discusses what it took for investigators to determine who is likely responsible for the murders of four girls in an Austin yogurt shop in 1991.

​ In an exclusive interview with CNN, a Texas cold case detective discusses what it took for investigators to determine who is likely responsible for the murders of four girls in an Austin yogurt shop in 1991. Read More Breaking News, Latest News and Videos | CNN