Investigators believe the main suspect in the Madeleine McCann case could be responsible for the disappearance of two other children.
The key suspect in the case, a German pedophile named in media reports as Christian Brueckner, 43, regularly lived in the Portuguese coastal village of Praia da Luz between 1995 and 2007 and was there at the time of the 3-year-old’s disappearance.
Brueckner is currently serving a prison sentence for multiple sexual offences.
The UK's Metropolitan Police said it had received more than 270 calls and emails since revealing details of the new suspect.
German prosecutors say they are investigating the possible link between the McCann case and that of a German girl, Inga Gehricke, who went missing five years ago but that they lack decisive evidence to charge a murder suspect.
"It is not yet enough for an arrest warrant or an indictment," said Hans Christian Wolters of the Braunschweig public prosecutor, which is leading the investigation.
Inga was 5-years-old when she disappeared without trace while on a family trip to a forest near the town of Stendal on May 2, 2015.
Despite a thorough search and investigation, police were unable to determine what became of the girl.
7News reports Germany’s Federal Criminal Police Office have also now contacted the family of German boy René Hasee, 6, who vanished in 1996 with the boy’s father telling German newspaper Kölner Stadt-Anzeiger that police told him “there could be a connection”.
René was last seen while on holiday in Aljezur in June 1996, just 40km from Praia da Luz.
Investigations are in the early stages, with authorities saying they would check whether there were any indications of a connection between the disappearances.
The German authorities have yet to explain what led them to conclude their current suspect was involved in Madeleine's disappearance or why they believe she is dead.
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