London: Police have found traces of blood in Madeleine McCann's holiday bedroom. DNA tests are being carried out to see if they came from the missing four-year-old.

If the blood is Madeleine's, it would change the whole nature of the inquiry by introducing the possibility that she died there rather than being kidnapped. Officers from the McCanns' home force in Leicestershire used specialised equipment and their own sniffer dogs to re-examine the two-bedroom apartment in the Algarve resort of Praia da Luz.

Windows were blacked out with plastic sheeting and tape to let technicians use ultraviolet light to scan for fingerprints, fibres and minute specks of blood invisible to the naked eye.

They found blood on a wall in the bedroom where Madeleine had been sleeping with her younger brother and sister on May 3. Police sources quoted in a Portuguese newspaper said there were signs someone had tried to wipe the stains.

Sniffer dog

A source close to the investigation said one of the sniffer dogs "stopped dead at the spot on the wall" and barked to indicate it had found something.

If the blood is found to be Madeleine's, one possibility is that it was shed in the course of her abduction.

But a Portuguese newspaper claimed yesterday that police now believe the little girl may have been killed or died in "an accident" in the bedroom.

National daily Jornal de Noticias reported: "This evidence locates Madeleine's death inside the apartment, but the investigators are still not certain it was murder, despite the fact that forensic experts have revealed that somebody did try to erase the blood traces.

"The theory most favoured by detectives to explain Maddy's death, now taken as almost certain, is that it involved an accident.

"The investigators are convinced that the blood belongs to Madeleine, but they are still holding back the detailed results of the tests until their suspicions are confirmed."

Repeat questioning

Sources said Madeleine's parents, doctors Kate and Gerry McCann, and the nine friends who were on holiday with them would be questioned again.

The British officers had offered to help in the case from the beginning but it was only 90 days into the investigation that they were allowed to share their expertise. Mark Williams-Thomas, a former Surrey detective and now a leading child protection expert, said the blood should have been found and analysed earlier. "I am staggered it has taken so long," he said.