A maid who is alleged to have abducted Madeleine McCann as revenge for being fired from the vacation resort where the missing girl was staying is being investigated by Portuguese police.

The identity of the maid was e-mailed to the official website of the Prince of Wales at the end of last week. Police have confirmed that the woman had worked at the Ocean Club resort in Praia da Luz. They have also discovered that the e-mail appeared to have been sent from a computer with an IP address in the Iberian peninsula.

Clarence House immediately informed Scotland Yard of the tip-off and forwarded the details to officers from Leicestershire police, who are leading the inquiry in Britain. The Prince and the Duchess of Cornwall issued a statement soon after Madeleine went missing saying that they were following the case “closely and with deep concern”.

A source close to Madeleine’s parents, Kate and Gerry McCann, said, “We hope that the police will follow up any information given to them. Kate and Gerry are encouraged by anything that focuses on finding Madeleine.”

Portuguese detectives have already completed checks on members of staff at the Ocean Club complex when Madeleine was reported missing on May 3, and have been attempting to track down former employees.

Other residents of the resort complex claimed that they suspected a member of staff could have been involved in a series of burglaries at the Ocean Club in the weeks before Madeleine disappeared 151 days ago.

Details of the tip-off came as a Portuguese newspaper reported that detectives believe Madeleine died by falling down a short flight of stairs at the ground-floor holiday apartment. Two senior police sources allegedly told 24 Horas there were “strong suspicions” that the girl had smashed the back of her head against ceramic tiles on the steps.

However, there was a child-proof safety gate at the top of the only stairs that lead from the rear patio down to the street. The newspaper said that the Forensic Science Service in Birmingham had discovered samples which showed that Madeleine had died of a head wound. But it is highly unlikely that traces of bodily fluids and hair recovered from the McCanns’ apartment and hire car would allow for such a conclusion to be drawn.

Mr. and Mrs. McCann hope to be allowed to speak publicly for the first time since being made official suspects in her disappearance on September 7. The McCanns’ lawyers are expected to meet their counterparts in Lisbon this week to discuss how the couple can speak out without breaking the strict Portuguese law of judicial secrecy.

A source close to the family said: “They want to put their side of the story but do not want to antagonise the Portuguese police despite everything that has happened.”

Friends of the couple, from Rothley, Leicestershire, say they are desperate to refocus the media’s attention on the hunt for their daughter. Details of an £80,000 advertising campaign in Spain, Portugal and Morocco are expected to be announced later this week.

The McCanns are particularly keen to promote the search in Morocco following a number of unconfirmed sightings. One sighting last week turned out to be a local girl.

A new sighting was reported yesterday, when James Valarino, 65, from Gibralter, said he was convinced that he had seen Madeleine in the town of Tangiers with a north European man on August 8. The man ran off with the girl when Mr Valarino called Madeleine’s name, the Sunday Express reported.