Police papers detailing the inquiry into the disappearance of Madeleine McCann are expected to be passed to the public prosecutor in Portugal later.
The family arrived at their home together on Sunday
All the police's information will be reviewed, three days after her parents, Kate and Gerry McCann, of Rothley, Leics, were named as formal suspects.
Meanwhile, police and social services in Leicestershire met to discuss their response to the case.
Madeleine, four, was last seen in the McCanns' Algarve apartment on 3 May.
Mr and Mrs McCann, both 39, returned to the UK on Sunday with their two-year-old twins, Sean and Amelie, but can be recalled to Portugal with five days' notice.
Police and representatives from Leicestershire social services met on Monday afternoon to discuss Madeleine's disappearance and the naming of her parents as suspects.
The McCanns are being advised by London-based lawyers Michael Caplan QC and Angus McBride in the wake of their naming as suspects.
Mr Caplan acted for former Chilean dictator General Augusto Pinochet when Spain attempted to extradite him from the UK in 1999.
Mrs McCann's uncle, Brian Kennedy, said on Monday the couple had received many messages of support.
"They're fine. They had a decent night's sleep and the twins slept soundly. They're holding up extremely well."
He added that the couple would not be going back to work immediately - both are doctors - but would try to lead "as normal an existence as possible".
BBC correspondent in Portugal Alison Roberts said the public prosecutor would undertake a review of the investigation so far, including the statements given by the McCanns last week.
This is normal practice when there is a significant development in a case.
"It seems unlikely, given this development, that the investigation will go beyond the normal eight months for a Portuguese inquiry," our correspondent said.
Under the Portuguese legal system, police have eight months to investigate a case before requiring permission to continue their inquiries.
No bail conditions, travel restrictions or charges have been imposed on the McCanns, who were questioned separately for more than 24 hours last week.
Independent criminal lawyer Dr Joao Oliveira Trindade told the BBC that the prosecutor had several options.
He could recommend the investigation continue, he could choose to charge the McCanns with a crime or he could place some restrictions on their movements, Dr Trindade said.
But to do the latter, Dr Trindade added, the prosecutor would have to decide on the type of crime he believed had been committed - specifically whether it was a "homicide", and if so, whether it was intentional or unintentional.
Officially a suspect
Bestowed by police or requested by individual
Right to remain silent
Right to a lawyer
Media reports, unconfirmed by police, have said that Portuguese officers have been preparing to make searches.
They are still awaiting further results from forensic tests, carried out in the UK, on samples taken from the apartment in Praia da Luz used by the McCanns and at least one vehicle used by the family and their friends.
Partial results from these tests triggered a series of events which led to the McCanns being declared formal suspects, or "arguidos".
The McCanns told Sunday newspapers that they believed Portuguese police were trying to frame them and had put Mrs McCann under pressure to confess that she killed her daughter by accident.
During an 11-hour interview, detectives suggested to Mrs McCann that traces of Madeleine's blood had been found in the family's hire car, she said.
The family say this is impossible as they did not rent the vehicle until 25 days after Madeleine disappeared.
Allan Scott, a lecturer at the University of Central Lancashire's School of Forensic and Investigative Sciences, said cross-contamination needed to be considered.
He said "secondary transfer" of Madeleine's DNA may have occurred and that DNA is "so sensitive" that if two people met in the street and shook hands and then one committed a crime, they could possibly leave the other person's DNA at the scene.