The Daily Mail newspaper in the UK today reported that a "substantial" amount of Madeleine McCann's hair was found in the vehicle hired more than three weeks after she vanished from the bedroom of her family's holiday unit in Portugal.
The revelation comes days after the McCanns were named as suspects by Portuguese investigators.
According to The Daily Mail, Portuguese detectives told the public prosecutor that the only explanation was that the hair came either from her body or from something used to wrap it.
Sources also told the newspaper that bodily fluids found in the car - not necessarily blood - matched the four-year-old's DNA.
The revelations came as detectives handed a 10-volume dossier on the case of Madeleine's disappearance to the public prosecutor.
The file has since been delivered to a judge to investigate, prompting speculation the couple may have a case to answer.
The judge will will decide if there is enough evidence for either or both Mr and Mrs McCann to be returned to Portugal to stand trial.
Mr McCann updated his website blog for the first time since Thursday overnight and insisted he and his wife were "100 per cent confident" in each other's innocence.
Legal experts told The Daily Mail that the couple's status could be changed at any time to allow them to be summoned back to Portugal and placed under house arrest.
But indications last night were that police are convinced they already have enough evidence, even if they are ordered to conduct more searches, tests or interviews.
The couple returned to their home in Leicestershire over the weekend.