Portuguese police have interviewed Kate McCann, mother of missing four-year-old Madeleine, for 11 hours.
Kate McCann said she was happy to help police with their enquiries
Her husband Gerry is expected to be questioned on Friday afternoon about Madeleine's disappearance from an apartment in Praia da Luz on 3 May.
Mrs McCann had been interviewed before by police, but this was the first time her lawyer had been present.
She was questioned as a witness until after midnight on Thursday. Police have said the McCanns are not suspects.
Separately, Portuguese detectives confirmed they had the partial results of forensic tests by a UK laboratory.
Madeleine, of Rothley, Leicestershire, disappeared from the family's holiday apartment while her parents were eating in a nearby restaurant.
Mrs McCann was driven to the police station in the Algarve by her husband, arriving at 1400 local time (1400 BST). She entered the police station with her sister-in-law.
In a statement released before the interview, she appealed to her daughter's abductors, saying: "It is not too late - please let her go or call the police."
She said: "We came to Portugal an ordinary family of five. We just want to know what happened on 3 May and want to be able to go home one family, reunited."
Family spokeswoman Justine McGuinness, speaking shortly after Mrs McCann entered the police station, said: "Kate and Gerry are happy to help the police in their investigations to find their daughter Madeleine, as they have been since she was taken.
"Kate continues to believe that Madeleine is still alive, and to hope and pray that she will be returned soon.
"Kate is a loving, gentle mother - one of the victims in an extraordinary and terrible set of events."
Mrs McCann emerged from the police station at about 0100 local time (0100 BST).
Her lawyer, Carlos Pinto de Abreu, made a brief statement in which he stressed she was treated as a witness throughout the questioning and that work to find Madeleine was ongoing.
Mr McCann is expected to attend Portimao police station at about 1400 local time (1400 BST) on Friday to be formally interviewed.
Samples, including suspected traces of blood, have been recovered from the McCanns' holiday apartment.
The UK's Forensic Science Service has spent the past month analysing them.
Madeleine was last seen on 3 May
Portuguese police spokesman Chief Inspector Olegario Sousa said partial results from tests had been received, but would give no further details.
Last week, the McCanns launched a libel action against a Portuguese newspaper which claimed they killed their daughter.
A public statement from the director of police followed, saying the McCanns had never been viewed as suspects.
The McCanns have travelled extensively through Europe to raise awareness of the search for their daughter.
The only person officially regarded as a suspect by police is Briton Robert Murat. He has not been arrested or charged.
He told BBC correspondent Richard Bilton that he had not had contact with the police for a few weeks.