The Irish woman had reported the alleged attack in 2004 but it was only when she recognised the photograph of Christian B in the media earlier this year - in connection with the McCann case - that she contacted authorities again.
The main suspect in the disappearance of British girl Madeleine McCann is the subject of a new criminal inquiry, it has emerged.
'Christian B' is now being investigated over the rape of a young Irish woman in 2004 in the Algarve region of Portugal, say prosecutors.
The alleged incident happened three years before the disappearance of McCann, according to German authorities.
McCann, then three, went missing from an apartment her family was staying in at the Praia da Luz resort on 3 May 2007.
In June 2020, British and German police identified Christian B - currently in jail in Germany for an unrelated offence - as the prime suspect in the case.
The Irish woman had reported the alleged attack in 2004 but it was only when she recognised the photograph of Christian B in the media earlier this year - in connection with the McCann case - that she contacted authorities again.
"I can confirm to you that we are also investigating the suspicion of rape of a young Irish woman in 2004 in the Algarve (the region where Madeleine McCann disappeared)", German prosecutor Hans Christian Wolters told AFP.