Portuguese police are investigating whether a suspect in the Madeleine McCann case may also be linked to a rape in the Algarve three years before.
Child sex offender Christian B is being investigated over possible links to an attack on an Irish woman.
Hazel Behan, 37, waived her right to anonymity to speak about the assault near Praia da Luz in 2004.
Officers say they will pass on any evidence to their German counterparts probing the disappearance of Madeleine.
A police source told BBC Europe correspondent Gavin Lee they have “credible information” that 43-year-old German man Christian B may be linked to the rape of Ms Behan, who was working in the region as a holiday rep in 2004.
No suspect was ever identified in her case and forensic evidence is understood to have been destroyed.
However, it has since come to light that a year after her alleged attack, Christian B was convicted of a similar rape in Praia da Luz.
Ms Behan said she felt physically sick when s