The family in Iowa whose situation I described wanted to find their son, very badly. From all accounts, they were a typical farm family, active in their church, no history or suspicion of child abuse or any other criminal activity.
Their basement wasn't unused. In the story after the body was found, one of the excuses law enforcement personnel used for not finding the body was that the basement was crowded with stuff stored down there.
Plus, I imagine the basement was used a couple times a year as a tornado shelter (I live very near their area).
Law enforcement personnel searched their house not just once but several times. Initially in the search for the missing boy, then in an effort to find evidence of a homicide.
One of the morals of the story is to never underestimate the resourcefulness of 13 year old kids who have something they want to hide (




mags and women's underwear). I actually wonder if the brother found the body because he, too, wanted a secret hidey-hole and suddenly wondered if there was something behind those old boards.
The other moral is that sometimes it's more difficult to search a house than it might seem.