This episode is loosely based on the West Memphis Three (Google it) three wrongfully convicted guys in Arkansas who, unfortunately, have not been the beneficiaries of a good team of police investigators. The acting in the episode is excellent. For those of us who have followed the WM3 for many years, it is chilling to watch this. It departs from the case its based on, but has many of the same elements. The probable actual killer was the stepfather of one of the kids and his wife found a pocketknife in the stepfather's drawer that the child "always" had with him.
For anyone interested, there is a great yuku board on the case.