A German man who travelled around Portugal in a camper van is now being investigated as a suspect in the disappearance of Madeleine McCann.
The British girl, who was aged three at the time, is “assumed to be dead”, according to German prosecutors who are running the investigation.
Police believe the 43-year-old suspect, who is now in jail for a sex crime, was in the area where Madeleine was last seen.
The suspect, who has not been officially named by police, is described as being white with short blonde hair, possibly fair, and about 6ft tall, with a slim build.
When did Madeleine go missing?
Madeleine vanished on 3 May 2007, just before her fourth birthday, and would have turned 17 last month.
Christian Hoppe, from Germany's Federal Criminal Police Office (BKA), told the country's ZDF television channel that the suspect is currently serving a prison sentence for a sex crime and has two previous convictions for "sexual contact with girls".
Scotland Yard is now launching a joint appeal with the BKA and Portuguese Policia Judiciaria (PJ), including a £20,000 reward for information leading to the conviction of the person responsible for Madeleine’s disappearance.
The investigation by the Metropolitan Police has identified more than 600 people as potentially significant and police were tipped off about the German national, already known to detectives, following a 2017 appeal 10 years after she went missing.
German police are treating her disappearance as a murder investigation.
However, the Met’s Operation Grange, launched in 2013, said the case remains a missing person inquiry as it does not have “definitive evidence” as to whether Madeleine is alive or not.
The London police force said the German authorities had taken the lead at this stage of the case as the German suspect is in custody in their country.
What has happened since her disappearance?
Here is a timeline of key events that have happened since Madeleine McCann disappeared 13 years ago:
3 May 2007
Parents Kate and Gerry McCann leave their three children, Madeleine, Amelie and Sean asleep in their apartment in Praia da Luz in Portugal, while they have an evening meal with friends. Three-year-old Madeleine later goes missing from her bed and an investigation is launched the following day by Portuguese police.
3 August 2007
Police officers publicly acknowledge that Madeleine could be dead, 100 days after her disappearance.
7 September 2007
Kate and Gerry McCann are questioned by Portuguese police and are named as official suspects in the case.
2 October 2007
Portuguese detective Goncalo Amaral, who was in charge of the inquiry, is removed from the case after criticising British police in an interview with a Portuguese newspaper. He was replaced by senior detective Paulo Rebelo on 9 October.
19 March 2008
Kate and Gerry McCann are awarded £55,000 in libel damage and front-page apologies from the Express Newspapers following allegations they were responsible for their daughter’s death.
21 July 2008
Portuguese authorities end their investigation and remove Kate and Gerry McCann as suspects in the case.
Scotland Yard launches Operation Grange, which is led by the Metropolitan Police Service to review the circumstances of Madeleine’s death.
25 April 2017
Metropolitan Police Assistant Commissioner Mark Rowley says the police are pursuing a “significant line of inquiry”. However, it is stressed there is still no “definitive evidence” as to whether Madeleine is dead or alive.
5 June 2019
The government announces it will continue to fund Operation Grange until 31 March 2020. It is also confirmed by the Home Office that £11.75 million has been spent on the operation since 2011.
3 June 2020
Scotland Yard identify a 43-year-old German prisoner as the main suspect in Madeleine’s disappearance.
A fresh appeal for information
Detective Chief Inspector Mark Cranwell announced on 3 June that he was taking the “really unusual” step of releasing two mobile numbers as part of the appeal for information.
Police released details of the German suspect’s phone number, (+351) 912 730 680, along with the number of a Portuguese mobile, (+351) 916 510 683, which dialled him while in the Praia da Luz area, starting at 7.32pm and ending at 8.02pm on the night of 3 May 2007.
Police want the person who made this call to come forward.
A statement from Madeleine's parents said: "We welcome the appeal today regarding the disappearance of our daughter Madeleine.
"We would like to thank the police forces involved for their continued efforts in the search for Madeleine.
"All we have ever wanted is to find her, uncover the truth and bring those responsible to justice.
"We will never give up hope of finding Madeleine alive, but whatever the outcome may be, we need to know as we need to find peace. We will be making no further comment in relation to the appeal today.
"We would like to thank the general public for their ongoing support and encourage anyone who has information directly related to the appeal to contact police."