A German prisoner with previous convictions for sexually assaulting girls has been identified as a suspect in the long-running Madeleine McCann case.
A 43-year-old who travelled to Portugal in a campervan is now the focus of Scotland Yard's investigation into her 2007 disappearance.
The then 3-year-old from England went missing during a family holiday in Portugal 13 years ago.
On the German version of Crime Watch today, German police revealed the suspect had previous convictions for sexually assaulting girls and was thought to have burgled hotels and holiday apartments.
Police said he was currently in prison in Germany.
According to the BBC, police revealed they were appealing for information about the campervan and the suspect's other vehicle - a Jaguar which the man transferred into someone else's name the day after Madeleine vanished.
"Someone out there knows a lot more than they're letting on," DCI Mark Cranwell, who's leading the Metropolitan Police inquiry, told BBC.
Police have released images of the campervan and Jaguar and are urging anyone with information to come forward.
Mr Cranwell said the prisoner, then aged 30, frequently visited the Algarve between 1995 and 2007, staying for "days upon end" in his campervan and living a "transient lifestyle".
The man made a half hour phone call around the time Madeleine went missing and police want the recipient of the call to come forward. Police are also asking for information connected to the number he took the call on.
"They're a key witness and we urge them to get in touch," Mr Cranwell said.
"Some people will know the man we're describing today... you may be aware of some of the things he's done.
"He may have confided in you about the disappearance of Madeleine.
"More than 13 years have passed and your loyalties may have changed.
"Now is the time to come forward."
Madeleine's parents Gerry and Kate said in a statement today: "We'd like to thank the police forces involved in Britain, Germany and Portugal."
They said they wouldn't give up on finding Madeleine alive and wanted to find out what happened to her so they could find peace.
The case is still being investigated as a missing person case as it is unknown whether or not Madeleine is alive or dead.
However, it is classed as a murder inquiry by German investigators at the Federal Criminal Police Office, the Bundeskriminalamt (BKA).