This week Billy and Paul look into the murder of 5-year-old Siobhan McGuinness from Missoula, Montana. Her case was recently solved with genetic genealogy, but identifying her killer only brought on more questions. Could he be responsible for other murders--including the Alphabet Murders?

The guys are joined by Special Deputy Susan Lane from the Missoula County Sheriff's Office and Investigator Colin Taft from Bath Police Department. Plus, we have an update on the Rebekah Gould murder case.