I despise McCain as much as the next one, but you need to cite reliable source information for a claim like that.
http://www.theamericanconservative.com/articles/mccain-and-the-pow-cover-up/
http://www.youtube.com/watch?v=IMcYqtayU7c
http://tomohalloran.com/2013/06/20/john-mccain-communist-traitor/