Where is or was the father. Things like this were less common when mom and dad lived together til death do they part.
Violent crime, including crimes against children has been in a steady decline. Our violent crime rates are now the same as they were when Kennedy was President. It is the "perception of crime" that has increased.
Despite Amber Alert hysteria, crimes like this are very rare, which is why these types of crimes make national news when they happen. Of all murdered children under the age of five (and, yes, I realize this victim was seven but I doubt the statistics are much different) only 3% are murdered by a stranger.