An investigation may not be relevant or necessary. It may have occurred through innocence and/or ignorance between curious children.
That would be discovered in an investigation would it not? I was under the impression that certain circumstances trigger automatic protocols to be followed, such as pregnancy under a certain age. Then again, the article doesn't say what state this occurred in, only the North East if I remember right, so I don't know if laws like that are in place.
Either way I just think this kind of thing is wrong.
Edit: MOFS described it well, though thats in the UK, I don't know if individual states have these laws.