How criminalist analyzed Diane Downs' crime scene

Jim Pex, former criminalist with the Oregon State Police Crime Detection Lab, explains how he used dolls and strings to help the 1983 investigation into whether Downs herself shot her three children. SUBSCRIBE to ABC NEWS: https://www.youtube.com/ABCNews/ Watch More on http://abcnews.go.com/ LIKE ABC News on FACEBOOK https://www.facebook.com/abcnews FOLLOW ABC News on TWITTER: https://twitter.com/abc GOOD MORNING AMERICA'S HOMEPAGE: https://www.goodmorningamerica.com/