They are now appealing for more information in the hope of bringing a suspect under investigation to court.
The investigation into Madeleine's disappearance from Praia da Luz, Portugal, has attracted renewed attention after authorities announced they were investigating a 43-year-old convicted German child sex offender.
The suspect is reportedly serving a seven-year prison sentence for the rape of a 72-year-old American woman in 2005.
He is known to have lived on the Algarve coast and his mobile phone received a half-hour phone call in Praia da Luz around an hour before Madeleine, then three, went missing on May 3, 2007.
German authorities have said they believe Madeleine is dead and are investigating the man on suspicion of murder.
Hans Christian Wolters, a spokesman for the Braunschweig public prosecutor's office, said yesterday that they have some evidence that Madeleine is dead but not have enough for a trial.
Mr Wolters told Sky News: “The hard evidence we don't have, we don't have the crucial evidence of Madeleine McCann's body.
“We expect that she is dead, but we don't have enough evidence that we can get a warrant for our suspect in Germany for the murder of Madeleine McCann.
“At the moment, we also don't have enough proof for a trial at court, but we have some evidence that the suspect has done the deed.
“That's why we need more information from people, especially places he has lived, so we can target these places especially and search there for Madeleine.”
Mr Wolters called on British tourists who visited Praia da Luz between 1995 and 2007, when the suspect is thought to have lived in the area, to come forward with any information.
British police are stoll treating Madeline’s disappearance as a missing person inquiry because there is no ‘definitive evidence whether Madeleine is alive or dead’.
She vanished shortly before her fourth birthday, while her parents were eating dinner with friends at a nearby tapas restaurant, and would have turned 17 last month.