I saw a really good documentary where an official behaviour expert [someone who works with the FBI and police] looked at the latest McCann interview and concluded that Madeleine was drugged in order to sleep deeper and not to wake up and find herself alone. After all the parents are both doctors. He also concluded that Madeleine did wake up but was so drowsy that she fell down the stairs and died. Comments such as 'I held her for the last time' by Mrs McC. and other statements seemed very convincing to me. Obviously in order not to lose their licences for drugging their children, the McCanns then made up a story of kidnapping. The guy then concluded that they know where M is buried.

This makes also a lot of sense to me. Even though the being kidnapped by sex traffickers is also still high on my list but I do believe that the McCanns were aware/part of it. Either way they are not as innocent as some them make them out.

For anyone who is interested in the interview: The McCann's Embedded Confessions