• Police admit there's 'nothing concrete' for prosecution
• 'Madeleine died from an overdose of sedatives'
• Kate's diary says 'she struggled with hyperactive children'
• Holiday friends to be interrogated by detectives again
Portuguese police do not have enough evidence yet to charge Kate and Gerry McCann over the disappearance of their daughter Madeleine.
Senior sources admitted there was "nothing concrete" to bring a prosecution.
A source at the Policia Judiciara said today: "There are lots of indications but without more elements it is impossible to determine what has happened in the almost four hours vital to the case from 6pm [on 3 May, when Madeleine vanished].
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Kate (with Madeleine's toy Cuddle Cat) and Gerry McCann were today driven for talks with their lawyer at a secret location
"Even if we confirm the blood and other remains taken from the car or the apartment correspond 100 per cent to the girl's DNA that does not prove anything.
"These elements would only just about confirm that the girl was in the apartment, which is obvious, and in the car.
"In either of these two cases that would not prove homicide, just that the body of the girl had been transported in the car.
We don't know if Maddy is dead and if she is how it happened. We have nothing concrete."
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Hire car: A senior source has said even if 'evidence' found in the car corresponds to Madeleine's DNA 'that does not prove anything'Police in Portugal are still awaiting vital test results from the Forensic Science Service in Birmingham on blood stains found at another apartment.
The Mail's sister paper, the Evening Standard, has been told the apartment being scrutinised is next door to the one from which Madeleine disappeared, and police believe it may hold the key to where her body could have been stored in the hours afterwards.
Today's development came after reports that Madeleine died from an overdose of sedatives.
Police are working on the theory that she was repeatedly drugged by her parents, the Evening Standard reveals.
Murat denies joining the search for Madeleine on May 3, when she went missingDetectives in the Algarve have asked British forensic experts to look for evidence that the toddler was given pills on the night of her disappearance and on earlier occasions.
The aim is to show that an alleged overdose that police appear to believe killed Madeleine was not a "one-off" accident or caused by the child mistakenly taking the drugs.
Instead, police want to show that use of drugs on the four-year-old was part of a pattern of behaviour that would have ended with her death.
Today's revelation follows the claim by a French newspaper that forensic results show Madeleine died after taking a "large quantity" of sleeping pills.
It would also explain why detectives this week applied to seize Kate McCann's diary, which is understood to describe how she struggled to cope with her "hyperactive" children.
Alleged extracts from the diary, published in two Portuguese newspapers, say the 39-year-old GP found it difficult to control Madeleine and her twin siblings, and the effort sapped her strength and emotions.
The McCanns have always denied sedating Madeleine and have described such claims as "ludicrous".
Police have asked scientists who have been testing samples from the McCanns' Renault Scenic hire car, rented 25 days after she went missing, to check for traces of drugs.
The samples allegedly include Madeleine's bodily fluids and hair, and the test can be done by examining strands of hair which absorb drug traces.
As they grow, the hairs create a "timeline" of consumption that can date back weeks or months.
Sources close to the investigation expressed caution about the claim that forensic tests "proved" Madeleine died from an overdose.
Preliminary tests carried out at the Forensic Science Service laboratory in Birmingham, sent to Portugal last week, are understood to give "indications" that Madeleine had ingested drugs.
Further results have been sent to Portugal this week.
Today the McCanns were driven from their home in Rothley, Leicestershire, for talks with their lawyer at a secret location.
They left in a silver BMW driven by solicitor Angus McBride. Mrs McCann's parents Brian and Susan Healy followed in another car.
Immediately afterwards Gerry's sister Trish Cameron drove the couple's two-year-old twins Sean and Amelie away.
Earlier it emerged that close friends of the McCanns will be interrogated by detectives in coming days.
Senior police sources say officers want to question further at least some of the seven friends who were holidaying with the McCanns when Madeleine vanished from the family's apartment on 3 May.
It is thought Russell O'Brien and his partner Jane Tanner are among those who will be quizzed.
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Jane Tanner and Russell O'Brien are among the McCanns' friends due to be quizzed againQuestions will be asked on alleged confusion over timings as the party sat down for dinner at a tapas bar, yards from where Madeleine was sleeping in the Mark Warner complex in Praia da Luz.
Ms Tanner has already told police she saw a man carry a child from the apartment wrapped in a blanket.
Mr O'Brien said he left the dining table at one point to look after his young daughter, who was ill.
The friends could be asked to return to Portugal early next week.
Police are also looking at either travelling to Britain, or using British officers to carry out the interviews.
However, it is understood nothing has emerged in recent days to shift the focus of the inquiry from Madeleine's parents.
There is growing anger among those close to the McCanns. They claim police have bungled, are making Madeleine's parents "scapegoats", and are determined to find the couple guilty at all costs of killing Madeleine.
Today they accused detectives of failing to investigate fully the only other formal suspect in the case, Robert Murat.
Close friends of the McCanns remain convinced Mr Murat is still the most likely suspect, although he denies any involvement and the police investigation into him appears to have drawn a blank.
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Robert Murat was named as an arguido - an official suspect - early in the investigationLike the McCanns, Mr Murat has been named an arguido - a formal suspect. Sources close to the couple insist he lied about his whereabouts on 3 May.
Mr O'Brien, Fiona Payne and Rachael Oldfield - all friends of the McCanns - and a Portuguese local have testified they saw Mr Murat helping the search for Madeleine on 3 May.
Mr Murat, who was born in Britain but grew up in Portugal, lives with his mother in a villa in Praia da Luz near the McCanns' apartment.
He is said to have introduced himself to the three friends on the night of the search, saying: "I'm Robert. Can I help?"
But he has denied this and insisted he spent the evening with his mother and girlfriend.
"I cannot believe Murat is no longer being investigated," said a source close to the McCanns.
"He is lying about being there on the night. They cannot understand why it hasn't been followed up why Murat lied. Kate and Gerry are being scapegoated."
Mr Murat, 33, insists he is the victim of a smear campaign.
He acted as a translator in the early days of the inquiry until suspicions about his behaviour began to grow.
No forensic evidence has linked him to the girl's disappearance.
Friends of the McCanns also cast doubt on the ability of Portuguese officers to carry out proper forensics work.
Today, a source suggested to the Standard that labels for findings from Mr Murat's vehicles may have got confused with labels from the McCanns' car. "They could easily have got the labels mixed up," said the source.
Read more: http://www.dailymail.co.uk/news/article-481789/Portuguese-police-dont-evidence-charge-Madeleines-parents.html#ixzz142C5VPoV