Gilgo Beach serial killer pleads guilty. Hawaii doctor learns his fate. Plus, reasonable doubt.

In Long Island, Gilgo Beach serial killer Rex Heuermann pleads guilty to murders spanning decades. The families of his victims speak out. In Hawaii, a verdict at the trial of anesthesiologist Gerhardt Konig, who is accused of attempting to murder his wife on a hike. Plus, a veteran prosecutor explains what reasonable doubt means in a jury trial. Help "Missing in America" win a Webby award.