Madeleine bed photo released

The first pictures showing the inside of the apartment where Madeleine McCann was sleeping when she disappeared have been released.

They are part of up to 20,000 previously secret documents, now made public by Portuguese police, which include witness statements, interviews with her parents, Kate and Gerry McCann, and other key evidence on the investigation.

Until now, Portugal's strict "segredo de justica" - or secrecy of justice - laws have limited the flow of information about the Madeleine inquiry.

She was nearly four when she vanished from her family's holiday apartment in the Algarve resort of Praia da Luz on May 3, 2007, as her parents dined with friends nearby.

Lawyers for Mr and Mrs McCann, from Rothley, Leicestershire, were formally given access to the police files last week, but are reluctant to respond to questions raised by journalists about the released documents.

The lawyers are studying the dossier for fresh leads that the couple's private detectives can follow up in their own search for their daughter.

McCann family spokesman, Clarence Mitchell, said: "The Portuguese Attorney General, in his recent statement, made it very clear indeed that there's absolutely no evidence of any wrongdoing by Kate and Gerry in any way, shape or form and journalists should bear that in mind when they examine the police files."

The police files reveal Mrs McCann refused to answer 48 questions put to her by Portuguese detectives.

She used her right as an "arguido", or formal suspect, to remain silent during a section of her interview.

Detectives started by asking Mrs McCann about her movements immediately after she discovered that her daughter was missing, a document in the police dossier shows.

She was asked where she looked, what she touched and whether she searched inside the master bedroom's wardrobe.

The 40th question was: Is it true that sometimes you despaired with your children's behaviour and that left you feeling very uneasy?

It was followed by: Is it true that in England you even considered handing over Madeleine's custody to a relative?

The police files show that detectives categorically told Mr McCann in an interview that Madeleine's DNA had been found in a hire car even though a British scientist warned the tests were inconclusive.

In an email in 2007 John Lowe, from the major incidents team at the Birmingham-based Forensic Science Service, said it was impossible to conclude whether the material came from Madeleine.

Mr Mitchell said: "You have to ask what the police were trying to achieve by over-presenting evidence that they did not have, and clearly could not claim to have."

Despite a huge police investigation and massive coverage in the Portuguese and British media, Madeleine has not been found.

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