The Portuguese authorities found, in the crime scene, the day after the abduction of Madeleine McCann, at least two fingerprints in the outside part of the shutters of the girl's room.
Those fingerprints, however, could not be valid to search for matches in police databases. But today, 13 years after, the technology of image processing has evolved. Maybe a reprocessing of the originals may result in valid images.
It should be of great importance to evaluate again, with new techniques, the evidence collected at the crime scene, on May 4, 2007.