Perhaps so, but you still have to have evidence and present it it in such a way it supports your case.
The prosecution missed doing so and so they lost the case. There was no conclusive evidence as to cause of death and who the killer was.
For a solid month you are searching for the babysitter and finally find her. She has been on vacation and says someone else took the child but all phone numbers, all leads, the ENTIRE story she tells is a lie, a provable lie.
The trunk of your babysitters car smells horrible - many people with experience claim it smells like a body was there. A hair from your child is found with the banding that shows during decomposition. You can't prove there was a body, but there are signs indicating there was. The entire state is searching for your child and finally, months later finds that child in a swamp, wrapped in a blanket you had left with the babysitter, AND there is a specific brand of duct tape inside that bag, appearing to look like it was across the face of your child.
Now, tell me the babysitter should walk free. That you would accept the babysitter had nothing to do with the death of your child.