But the force refuted the claim, saying: "Leicestershire Constabulary have been careful not to offer an opinion as to what has happened to Madeleine as it is not party to all the evidence as it is not our investigation."
Such a statement is unprecedented for the British force, which has been reluctant to provide a "running commentary" on the five-month-old case.
The move also highlighted the deep divisions between detectives in the McCanns' home county and those in Portugal. A British source linked to the inquiry said: "It appears that Portuguese police are resorting to dirty tricks to divert attention from their troubled investigation."
The stand-off between the two forces follows yet another controversial week in the search for Madeleine.