Police said they wanted to speak to a thus-far unidentified second person who spoke with the German suspect from a Portuguese phone number on May 3, 2007 at the time of McCann's disappearance.
The disappearance of Madeleine, who was vacationing with her family in the seaside village of Praia da Luz, in Portugal's Algarve region, sent shock waves across Europe, sparked an global manhunt and triggered years of speculation.
The suspect had lived in Portugal's Algarve region from 1995 to 2007, and also resided in a house in Praia de Luz, the resort town from which McCann disappeared, according to the Braunschweig prosecutor's office.
"It's been so long to actually find someone that might be responsible for what happened so long ago", said 20-year-old Daniel Westcottoy, who was at a nearby school when Madeleine disappeared.
The Jaguar which was transferred out of his name the day after Madeleine McCann's disappearance. "There are also indications that he may have made his living by committing crimes such as burglary theft in hotel complexes and holiday apartments, as well as drug trafficking".
The man is said to be white, with short blonde hair and about six feet tall, and had a slim build when Madeleine went missing.
German law enforcement officers have not explained what led them to conclude the man was involved in Madeleine's disappearance or why they believe she is dead.
The Metropolitan Police began reviewing McCann's disappearance in 2011, in an large-scale investigation known as Operation Grange that has cost at least £11.75m ($14.7) as of June 2019.
Her parents, Kate and Gerry McCann, have endured 13 years of hell.
Investigators have released images of both vehicles - a camper van and a Jaguar - as well as the phone number thought to belong to the suspect, and the number that was called.
A house in Portugal linked to the suspect
The 43-year-old German national is known to have been in and around Praia da Luz on Portugal's Algarve coast at the time Madeleine vanished on May 3, 2007.
"They do remain hopeful that she could still be found alive".
Now serving a long prison sentence for sex crimes against young girls, "Christian B" travelled around Portugal in a camper van and was believed to have been in the area where Madeleine was last seen before she went missing. "But they say that despite all that, whatever the outcome of this particular line of enquiry might be, they need to know as they need to find peace".
Police from Britain, Germany and Portugal launched a new joint appeal for information in the case Wednesday.
Though numerous suspects have come to light in the case previously, McCann family spokesman Clarence Mitchell said that it seems as if there is something different this time.
Undated handout photo issued by Metropolitan Police of a VW T3 Westfalia campervan that has been linked to the suspect.
In Praia da Luz on Thursday, local people wondered whether the riddle of what happened to Madeleine might finally be solved.
British police said however that they were still treating the case as a "missing person inquiry". "On 4 May 2007, the day after Madeleine's disappearance, the vehicle was re-registered to someone else in Germany".
German police chief Christian Hoppe last night went on the country's TV show XY - his country's version of Crimewatch - and revealed: "The investigation leads us to believe that Maddie McCann was killed".
"There has never been something as clear-cut as that from not just one, but indeed now three, police forces", he said.
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