Breanne's case - they found the killer and he confessed.
http://www.cnn.com/2011/CRIME/08/15/missouri.missing.girl/
Tori's case - Found killers. Pled guilty and confessed.
http://www.cbc.ca/news/canada/story/2010/12/09/tori-stafford-mcclintic.html
Chris Abeyta - Mother failed LDT x2. Viable suspect exists, but police department destroyed most evidence. Family has been searching for 25 years.
http://www.findchristopher.com/investigativefacts.html
Riley Fox - Father failed LDT. Father was coerced into a confession. Jailed for 8 months. DNA cleared him, and real killer found 5 years later.
http://abcnews.go.com/2020/riley-fo...charged-murder/story?id=10878773#.Tsj7gFbL_K8
Part of the problem is that many times it's impossible to PROVE that the parents didn't do something. So if they fail the LDT, but no one else is ever caught, they can't be used as *proof* that innocent people do fail LDTs. (Chris Abeyta for example). Think about the Ramsey's for instance. They were dragged through the mud for years - the most horrid things said about them... they were finally CLEARED, with the most impressive apology from an LE agency that I have ever heard, and yet some people STILL insist that the parents were guilty. (And no, I am NOT saying that the Ramseys failed LDT's - the case is an example of how hard it is to *prove* someone's innocence.)
So, theoretically, in many cases where the parents failed polygraphs but have not been charged or convicted, the parents are innocent. But they can't really be used since there is no way to prove it.