Two young women were sexually assaulted, strangled to death, and left on the side of the highway 30 years ago.  One in Texas and the other in California.  See how investigators used a popular genealogy DNA database to find the man responsible.  Investigators in Riverside, California, and the Texas Rangers never gave up hunting down the predator,  Douglas Thomas, for the 1992 murder of Shenda Denise Hayes and the 1993 murder of Sherri Herrera.