Detectives hoping to find out what happened to Madeleine McCann have travelled to Bulgaria to track down the wife of a convicted paedophile.
The new lead comes after Met detectives re-examined witness statements taken after Madeleine disappeared aged three.
They hope to interrogate the woman, whose husband was a paedophile but has died since Madeleine vanished in 2007, The Sun reported.
The couple were reportedly working as domestic helpers near the apartment in Portugal where the McCanns were staying on holiday.
However, they both vanished after the investigation into Madeleine’s disappearance was opened, it is claimed.
Locals in the Algarve reported them to the police, but despite extensive searches carried out in the following years, officers have been unable to find the woman.
A source told The Sun: ‘There is no evidence they were involved but it would be good to eliminate them from the investigation.’