The new suspect in the Madeleine McCann case has also been investigated over the disappearance of a German girl, according to German media reports.
The 43-year-old German man, named in reports as Christian B, is currently serving a prison sentence.
He is believed to have been in the area where Madeleine, three, went missing while on holiday in Portugal in 2007.
Meanwhile, a spokesman for the McCanns said they would be “encouraged” by the response to an appeal for information.
The UK’s Metropolitan Police said it had received more than 270 calls and emails since revealing details of the new suspect on Wednesday.
German prosecutors have said they are assuming Madeleine is dead and that the suspect is being investigated on suspicion of murder.
A number of German media reports said the suspect had been investigated over the disappearance of a 5-year-old German girl – named only as Inga.
She went missing from a family party in Saxony-Anhalt on 2 May 2015 and has never been found.
Police have refused to confirm the investigation or comment on a report which says officers searched an area of nearby land belonging to Christian B in February 2016.
On Thursday, German prosecutors said the suspect was “a sexual predator who has already been convicted of crimes against little girls” and was “serving a long sentence”.
Hans Christian Wolters, from the Braunschweig Public Prosecutor’s Office, said the suspect was regularly living in the Algarve between 1995 and 2007 and had jobs in the area, including in catering, but also committed burglaries in hotels and dealt drugs.
The Met Police, who are working with their German and Portuguese counterparts, said the case remained a “missing persons” investigation in the UK because it does not have “definitive evidence” as to whether Madeleine is alive or not.
Clarence Mitchell, a spokesman for Madeleine’s family, said her parents, Kate and Gerry McCann, from Rothley, Leicestershire, are “trying to maintain as normal a life as possible” and awaiting updates from police.
“Two-hundred-and-seventy calls and emails isn’t a bad result, given it was 13 years ago,” he said.
“They certainly will be encouraged to know the appeal is yielding results already and hopefully within that there will be crucial bits of information the police can act upon.”
Det Ch Insp Mark Cranwell, who is leading the Met’s investigation, known as Operation Grange,said he was “pleased” with information coming in after receiving more than 270 calls and emails by 16:00 GMT on Thursday.
Police have also released photos of two vehicles – a VW camper van and a Jaguar car – which are believed to be linked to the man, as well as a house in Portugal.
The day after Madeleine vanished in 2007, the suspect transferred the Jaguar to someone else’s name.
He was in the Praia da Luz area where the McCann family was staying when she disappeared and received a phone call at 19:32, which ended at 20:02. Madeleine is believed to have disappeared between 21:10 and 22:00 that evening.
Police have released details of the suspect’s phone number (+351 912 730 680) and the number which dialled him (+351 916 510 683), and said any information about these numbers could be “critical”.
Madeleine went missing shortly before her fourth birthday from an apartment in Praia da Luz on the evening of 3 May 2007 while her parents were with friends at a nearby tapas bar.
Her disappearance sparked a huge and costly police hunt across much of Europe – the most recent Metropolitan Police investigation, which began in 2011, has cost more than £11m.
The Madeleine McCann case: a timeline
- 3 May 2007: Alarm is raised after Madeleine is found to be missing
- September 2007: Kate and Gerry McCann are made “arguidos” – formal suspects – in their daughter’s disappearance
- July 2008: Portuguese police halt their investigation and lift the “arguido” status of the McCanns and another man, Robert Murat
- May 2011: Prime Minister David Cameron asks the Metropolitan Police to help investigate. A two-year review follows
- March 2012: Portuguese police launch a review of the original investigation
- July 2013: Scotland Yard says it has “new evidence and new witnesses” in the case and opens a formal investigation into Madeleine’s disappearance
- October 2013: Detectives in Portugal reopen the investigation, citing “new lines of inquiry”
- January 2014: British detectives fly to Portugal amid claims they are planning to make arrests
- December 2014: Detectives question 11 people who it was thought may have information on the case
- September 2015: The British government discloses that the investigation has cost more than £10m
- February 2017: Portugal’s Supreme Court dismisses a long-running libel case against Goncalo Amaral, former head of the local police investigation, ruling that his book, which alleged the McCanns disposed of Madeleine’s body, is protected by freedom of expression laws
- April 2017: The only four official suspects investigated by police are ruled out of the investigation but senior officers say they are pursuing a “significant line of inquiry“
- November 2018: An extra £150,000 is granted to continue the investigation. It is the latest in a series of six-month extensions which take the cost of Operation Grange to an estimated £11.75m
- March 2019: Netflix screens an eight-part documentary about Madeleine’s disappearance. Her parents, who did not participate in the film, feel it could “potentially hinder” the police investigation
- June 2019: The UK government says it will fund the Met Police inquiry, which began in 2011, until March 2020
- June 2020: Police reveal that a 43-year-old German prisoner has been identified as a suspect in Madeleine’s disappearance