Traces of blood have been found by British police in Madeleine McCann's holiday apartment in the Algarve, it was claimed yesterday.

DNA tests are being carried out to establish whether they came from the missing four-year-old.

A Portuguese newspaper reported that the discovery came after UK detectives were allowed to review the three-month investigation.

The Jornal de Noticias said the blood was discovered on a wall in the McCann's holiday apartment in the Algarve early last week by British sniffer dogs specially trained to find remains of bodies.

Police in the UK and in Portugal have refused to comment on the claims, which came as Madeleine's parents met police after a second search of the home of Robert Murat, the only official suspect.

Police failed to find any new evidence after a fresh two-day search at the villa in Praia de Luz he shares with his elderly mother which is near where Madeleine disappeared on May 3.

Mr Murat, 33, who denies any involvement with the disappearance, was present during most of the search.

Yesterday's developments in Portugal came as it emerged that a paedophile who was on holiday in the Algarve at the time when Madeleine went missing has been found dead after abducting a five-year-old girl.

Swiss police yesterday said DNA tests showed a link between Urs Hans Von Aesch, 67, who was found dead last week, and some belongings of Ylenia Lenhard, who is still missing a week after she disappeared.

Portuguese detectives have been told of similarities between the abductions of Madeleine and Ylenia, who both have blonde hair.

They have also been informed that Von Aesch, who lived in Spain, was thought to have been close to Praia da Luz when Madeleine disappeared.

Von Aesch is regarded by Swiss police as the key suspect in the abduction of Ylenia, who disappeared while walking to a swimming pool in the north-east of Switzerland last Tuesday.

Von Aesch had "direct contact" with Ylenia's backpack, helmet and the scooter, Bruno Fehr, chief of canton St Gallen criminal police, said yesterday.

The girl's clothing items were all neatly folded in her backpack, Mr Fehr said, suggesting she was left naked.

The backpack, was discovered in a forest 20 miles from where she was abducted. Von Aesch shot and injured a 46-year-old man in the same forest before killing himself last Tuesday.

Police have declined to comment on whether there was any link between Madeleine's abduction and Ylenia's disappearance.

In the Algarve, it emerged that up to 12 British and Portuguese police officers scoured Mr Murat's home over the weekend using hi-tech scanning equipment and a British sniffer dog. A green van and a grey hatchback car used by Mr Murat and his mother were handed over to the police yesterday.

It is believed the vehicles were examined in the presence of Mr Murat in a sealed off underground car park close to police headquarters.

Madeleine's parents met detectives yesterday for a routine update on the inquiry.

Portuguese police declined to comment about the results of the re-examination of the villa, citing Portugal's strict secrecy of justice laws. However, a source close to the inquiry told the Portuguese newspaper Diario de Noticias nothing was found.

Tuck Price, Mr Murat's friend and spokesman, said: "They (the police) haven't officially said anything But we were there, and I think we would have seen and known if they had found anything."

The second search of the villa, named Casa Liliana, began on Saturday when police combed the land surrounding the property, clearing undergrowth and cutting down trees. Police are also investigating a possible sighting of Madeleine at a restaurant in Tongeren, Belgium, on the Dutch border.

Madeleine's mother, Kate, has told a magazine her strong relationship with her husband Gerry, who was born in Glasgow, had helped her through the torment of the past three months.