Police investigating the disappearance of Madeleine McCann are focusing on a convicted German paedophile.
Martin Nye, 48, is already in prison and was not previously known to the investigators.
German officers have passed on his details to British and Portuguese detectives.
The potential breakthrough has prompted Portuguese police to plough more resources into the case.
Nye was jailed for life in 2012 for abducting and murdering three young children and abusing many more, The Sun reported.
The killer was reportedly known to haunt the Algarve and travelled throughout Portugal in the 1990s.
The news came on the 12th anniversary of Madeleine’s disappearance.
She was three when she vanished while on holiday with her parents in Praia da Luz on the Algarve coast on May 3 2007.
Metropolitan Police Commissioner Cressida Dick said the force was pursuing ‘active lines of inquiry’ and has asked for more funding from the Home Office in London.
British police launched their own investigation, in 2013 after a Portuguese inquiry failed to make progress.
Ms Dick said: ‘We have active lines of inquiry and I think the public would expect us to see those through.
A very small team continues to work on this case with Portuguese colleagues and we have put in an application to the Home Office for further funding.’
Madeleine’s parents, Kate and Gerry McCann, have always pledged never to give up the search for their daughter.
In a statement on Friday, the 12th anniversary of her disappearance, they said: ‘The months and years roll by too quickly, Madeleine will be 16 this month.
‘It’s impossible to put into words just how that makes us feel. There is comfort and reassurance though in knowing that the investigation continues and many people around the world remain vigilant.
‘Thank you to everyone who continues to support us and for your ongoing hope and belief.’