The man being treated as a suspect in the search for missing Madeleine McCann says he has been made "a scapegoat for something I did not do".
Robert Murat has worked for the police as a translator
Briton Robert Murat, 33, told Sky News the situation had "ruined" his life.
Police have searched his mother's Algarve villa, which is close to where four-year-old Madeleine, from Rothley, Leicestershire, was last seen on 3 May.
However, officers said they did not have the evidence to formally arrest or charge anybody.
Meanwhile, Madeleine's aunt, Philomena McCann, from Glasgow, is to visit the House of Commons in an effort to keep the search in the public eye.
Glasgow MP Mohammed Sarwar, who will accompany her, said the McCann family had "the full support of the British government".
Madeleine's grandmother, Susan Healy, said the latest developments have been distressing for her daughter, Kate.
"She's holding her own but it's difficult - information is always going to be sparse because that is the way that they work in Portugal," she said.
Mr Murat, who previously lived in Hockering, Norfolk, has recently been living with his mother Jenny, 71, in Praia da Luz.
Speaking off camera after 12 hours of questioning, Mr Murat reportedly told Sky News: "This has ruined my life and made my life very difficult for my family here and in Britain.
"The only way I will survive this is if they catch Madeleine's abductor."
Members of Mr Murat's family have insisted he had nothing to do with Madeleine's disappearance and say he was having dinner with his mother on the night it happened.
On Tuesday, Chief Inspector Olegario de Sousa told a news conference he could not confirm whether Madeleine was alive or dead.
He said police had searched five houses on Monday and seized "various materials" from the properties which were undergoing forensic tests.
It is believed two cars used by the Murats have been examined, and computers, mobile phones and several video tapes were taken away.
Two other people - a German woman and a Portuguese man - have been questioned as witnesses.
Officially a suspect
Bestowed by police or requested by individual
Right to remain silent
Right to a lawyer
Mr Murat has not been formally named by police as their suspect.
Mr Sousa confirmed the suspect had assisted police in the early stages of the investigation by working as a translator.
The suspect has signed an identity and residence statement that prevents him from moving house or leaving Portugal.
Mr Murat may have been designated a suspect by police, or he could have chosen to take the status himself to gain additional protections under Portuguese law.
An arrest can be made once someone is a suspect, but only if there is sufficient evidence.
Madeleine McCann disappeared on 3 May
Mr Murat, a former property developer who has a four-year-old daughter, had become well known to journalists during the search for Madeleine.
Police began questioning him and searching his mother's property, known as Casa Liliana, after Sunday Mirror journalist Lori Campbell spoke to the British Embassy and the police about him.
Madeleine disappeared from her bedroom 13 days ago as her parents ate dinner at a nearby tapas restaurant.
The international number for Crimestoppers is +44 1883 731 336. People with information about Madeleine can call anonymously.