Papers outlining the case against the parents of missing Madeleine McCann - now suspects in her disappearance - are expected to be passed to the public prosecutor today, Portuguese police said.
The Portimao-based prosecutor, Jose Cunha de Magalhaes e Meneses, will then decide whether to bring charges against Kate and Gerry McCann.
Chief Inspector Olegario Sousa, spokesman for the Portuguese police inquiry, said: “At the moment the inquiry is being prepared to be handed to the prosecutor in charge of the case.
“He will analyse it and after this he will make his decision.”
Asked when the papers would be handed over, he said: “Probably during today.”
Portuguese police decided to pass the file on to the prosecutor despite not having all the results from forensic tests being carried out by the Forensic Science Service in Birmingham.
Mr Sousa said: “The information is that we have received part of the forensic results, so we are waiting for the rest.”
The McCanns’ Portuguese lawyer, Carlos Pinto de Abreu, has said he has no idea how long it would take for the case to be concluded. It is understood the McCanns could have to wait months before learning whether they will be charged or cleared.
Portuguese detectives appear to be working on the theory that Mrs McCann killed her daughter by accident and covered up the death by claiming she was abducted.
FSS test results received in recent weeks have apparently boosted this hypothesis.
Mr McCann’s alleged role is not clear, but sources said police believe he was an accessory to the killing.
It is now 130 days since Madeleine went missing from her bed in her family’s holiday apartment in Praia da Luz while her parents dined at a nearby tapas restaurant.
Mr and Mrs McCann returned to their home in Rothley, Leicestershire, yesterday with their two-year-old twins, Sean and Amelie.
Philomena McCann, Madeleine’s aunt, said today it was “unbelievable” that Kate and Gerry McCann had been named as “arguidos”, or formal suspects, in her disappearance.
“The way the Portuguese have turned this investigation round, and they are no longer looking for a live child, they are assuming on spurious evidence, that Madeleine is now dead, well, we don’t agree with that in any shape or form,” she told BBC Breakfast.
“We want the investigation changed round to look for Madeleine alive, as we reckon she is.”
Ms McCann said the couple would be “absolutely” co-operating with the Portuguese police and were prepared to return to Portugal to undergo further questioning.
After touching down at East Midlands Airport just after noon yesterday, Mr McCann, his voice breaking, insisted they played no part in her disappearance.
He said: “Whilst it is heartbreaking to return to the UK without Madeleine, it does not mean we are giving up our search.
“As parents we cannot give up on our daughter until we know what has happened.”
The couple do not know if or when police will call them back to Portugal, although they will obey even if they fear they could be arrested, a family friend said.
“They are not running away. It is a change of place but they are very happy to help the police,” the friend said.
The family’s decision to return to Britain was in large part based on their desire to maintain a sense of normality for their two youngest children.
Mr McCann said: “We want the twins, as much as is reasonably possible, to live an ordinary life in their home country, and we want to consider the events of the last few days which have been so deeply disturbing.”
It is very unlikely they will bring the twins back to Portugal with them if police need them for further interviews, a friend said.
The McCanns’ return to Britain yesterday on board easyJet flight 6552 from Faro capped a week of dramatic developments.
Last Monday Portuguese detectives telephoned Mr McCann to summon him and his wife for further questioning.
Three days later Mrs McCann went to the headquarters of the Policia Judiciaria (PJ) - Portugal’s CID - in the town of Portimao and was questioned for 11 hours.
During the interview detectives suggested to her that traces of Madeleine’s blood were found in the family’s hire car, a silver Renault Scenic.
Mrs McCann is understood to have told them angrily there was “no way” this could be the case because they did not lease the vehicle until 25 days after her daughter disappeared.
She returned to the police station on Friday and was declared an “arguida”, or formal suspect.
Detectives asked her 22 key questions about what happened to Madeleine, including whether she accidentally killed her.
Mr McCann was separately interviewed for eight hours the same day and was also made an arguido.
There were no bail conditions attached to their arguido status and they retained their passports, meaning they could freely return to the UK.
On Saturday they couple made a last-minute decision to reinstate their original plan to fly home yesterday.
Mr and Mrs McCann are receiving further legal advice from two lawyers in the UK.
The couple are being advised by Michael Caplan QC and Angus McBride, from London firm Kingsley Napley.
Mr Caplan acted for former Chilean dictator General Augusto Pinochet when Spain tried to extradite him from the UK in 1999.
Mr McBride is a criminal lawyer with particular expertise in protecting the reputation of people and companies being investigated by either the media or criminal investigators, according to Kingsley Napley’s website.
A family friend said they were advising the McCanns on “much more than just extradition” but would not elaborate further.
The lawyers are expected to issue a joint statement later today.
Justine McGuinness, the McCanns’ spokeswoman, said the couple were unlikely to emerge from their home.
They are unable to say anything because of the “difficult legal situation” they are in since being named as formal suspects in the case of their daughter’s disappearance, she said.
Speaking to the media in Rothley village square, Mrs McCann’s uncle, Brian Kennedy, declined to comment on the latest developments in Portugal.
But in a statement issued to the Press Association, he said: “I have been asked to say that we would like all inquiries or requests for interview to be made through the family press spokesperson Justine McGuinness, who will handle these because of the present delicate situation in Portugal.
“Kate and Gerry are continuing to receive many messages of support and the children are fine.”
Mr Kennedy said his niece and her husband had had a decent night's sleep.
When asked if the couple would be returning to work, he added: “I imagine they will try to have as normal a situation as soon as possible.”
Portuguese newspapers reported that police were preparing fresh searches in Praia da Luz today.
These will take place to the south of the Ocean Club resort, where Madeleine went missing, according to Correio da Manha.
Mr Sousa refused to confirm or deny the reports, but said they did not come from the Policia Judiciaria.
It was also reported today that “biological fluids” with an 80% match of Madeleine’s DNA were found underneath the upholstery in the boot of the McCanns’ rented Renault Scenic.
The sample was too badly deteriorated to make a 100% match possible, according to the Diario de Noticias newspaper.
Mr Sousa was quoted as saying that the McCanns had the right to return to Britain but it would add delays and complications.
“The attitude is legal, but obviously will complicate the investigation because we now have to wait for the carrying out of legal formalities,” he told Correio da Manha.
It was reported today that Portuguese investigators will have to write a formal letter of appeal asking for the assistance of British police if they want to re-interview the McCanns.
But Mr Sousa denied this, saying: “It’s not necessary. They have a Portuguese lawyer.
“We could notify the Portuguese lawyer and after that the lawyer will talk to them because he represents them.”