Forensic tests on blood samples found in the McCanns' apartment in Praia da Luz are expected back in the coming days which will reveal whether the blood belongs to Madeleine or somebody else.
The McCanns will be anxious to hear the results before the information is leaked to Portuguese newspapers.
It was reported today that a regular meeting the McCanns have with the Policia Judiciaria was brought forward to discuss their growing concerns over insensitive leaks.
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More anguish: Kate and Gerry McCann
Latest unconfirmed reports have suggested Madeleine died in the apartment and then was possibly thrown from cliffs after her body was placed in a bin bag and weighed down with rocks.
A source close to the McCanns described the speculation as "sickening".
"They have had to cope with these reports for weeks now. They don't know where they're coming from - police or another source - but it's hurtful." There was further heartache for the McCanns today when it was reported that police believed their daughter was dumped at sea.
A Portuguese newspaper claimed police think Madeleine's body could have been stuffed into a sack and weighed down with stones.
A police insider said: "We know what happened to her. But we don't know why she died, whether it was accident or murder."
A friend of Kate and Gerry said it was deeply distressing for them to read stories this but they remain positive: "They pray Madeleine is alive and will be reunited with them soon."
"They just want to be kept informed of developments."
Meanwhile a British holidaymaker whose hire car was seized by police hunting for Madeleine McCann yesterday angrily denied any involvement in the case.
Jim Gorrod, 34, a solicitor from Exeter, was on holiday in Praia da Luz on the Algarve with his pregnant wife Charlotte and toddler son when the four-year-old went missing.
The Gorrods, who knew one of the couples on holiday with the McCanns, joined the search for Madeleine in the hours following her disappearance in May.
But three months later, the solicitor found himself under investigation and his Portuguese rental car being impounded for examination.
This led to speculation that a 'mystery' Briton might be linked to Madeleine's disappearance.
But Mrs Gorrod described the speculation as "ridiculous" and said detectives had cleared them of any involvement.
Her husband is said to have come under suspicion at a car hire office when he returned his vehicle two days after Madeleine went missing.
It is understood staff at the Sixt car hire office at Faro Airport thought it odd that a man on his own was returning a car with a rented baby seat.
The staff's concerns were farcical and could easily have been checked out, say the couple, because Mr Gorrod had dropped his family and luggage at the entrance to the busy airport before returning the car.
But the hire firm reported its concerns to police and waited to be contacted.
Astonishingly, it took three months for police to ask for the blue Opel Corsa, which had been rented out to at least six more customers since then, to be examined.
Yesterday, Mr Gorrod was revealed to be the mystery British driver being sought for questioning by the Policia Judiciaria.
He immediately issued a statementproclaiming his innocence and insisted a British detective had told him he had 'nothing to worry about'.
He said: "A British police officer directly liaising with the Portuguese investigation team recently contacted me to eliminate the vehicle I hired for the holiday.
"The car has been identified and I have been told by the British police officer that he has no plans to interview me or my family.
"We are of course deeply saddened by Madeline's disappearance and hope for her safe return."
Mr and Mrs Gorrod already knew two of the McCann group, Dr Russell O'Brien and his partner Jane Tanner because they live two streets away in Exeter and have a child of the same age.
But the Gorrods said they did not know they would be in the same resort and they did not travel with the Mark Warner holiday company or stay at the Ocean Club apartments.
During the week in Praia da Luz, they are said to have 'occasionally' bumped into their friends but never met Gerry and Kate McCann.
When Madeleine went missing, James Gorrod joined other holidaymakers in helping search for the child before taking his family home to Devon.
Then a week ago, during a review of the case by British detectives, the family's hire car was finally seized and examined by Portuguese police.