It seems likely at this point that it was their next door neighbor,so this doesn't really apply. How many people don't invite their next door neighbors in at one time or another?
It's not just swingers, many single women are good at exposing their kids to whoever also by bringing a trail of men into their children's homes.
It's not just swingers or single women inviting strangers into their houses,it's Norman and Norma Normal inviting in their priest,a child care worker,a trusted neighbor,or even a realtive. The sooner people realize there are no guarantees at all,the sooner they will wake up and start to protect their children from EVERYBODY that comes into contact with them by just starting to pay more attention.
Obviously. No matter who you invite into your home, if you have little ones, it's your responsibility to question why they are going into your childrens' bedrooms. Especially people you meet and bring home from a bar at 3am for a little "party".
Obviously these people have no sense. They could just as easily had their orgies away from their kids, they have cheap motels everywhere for that kind of thing and then only the parents would be exposed to a sex killer. I don't really care what they were doing, they've lost a child which should be punishment enough but they also apparently weren't exactly upfront with the police in the beginning even to help find their daughter and instead made up stories about doors being left unlocked. It was like they wanted to protect their orgy friends more than find their kid.