Former BBC journalist and communications consultant Clarence Mitchell told The Telegraph Maddie was "taken to order" by strangers.
Mr Mitchell - who has worked with Kate and Gerry McCann since 2007 - told the outlet: "I asked the British authorities what they think happened and if there was any family involvement.
"They assured me it was just a rare case of strange abduction."
The media expert also admitted "a sexual motive is an obvious possibility".
As reported by The Daily Star, Mr Mitchell believes Kate and Gerry are completely innocent of any involvement in their daughter's disappearance.
He blasted commentators who criticise the couple for leaving their children alone while they ate in the resort tapas restaurant, saying: "A lot of it is misinformed, misguided and based purely on assumptions or lack of knowledge."
According to a profile from The Sun, 57-year-old Mitchell has over 30 years experience in strategic communications with a client list which includes an Iraqi Prime Minister, the Government of Iceland and Microsoft.
He is also said to have helped the Costa Chairman and CEO with public relations in the wake of the Costa Concordia cruise ship disaster which killed 32 people when it crashed near the Italian island of Giglio in 2012.
See the explosive promo for The Disappearance of Madeleine McCann here..