Eighteen years after Madeleine McCann disappeared, a renewed search is being carried out this week in Portugal. Madeleine was just three years old when she went missing from a holiday resort in Praia da Luz on May 3, 2007.

Investigators believe that she is no longer alive, although her remains have never been found.

The current search effort is focused on areas between Praia da Luz and a property once occupied by prime suspect Christian Brueckner. While some evidence points to Brueckner’s possible involvement in Madeleine’s disappearance, authorities are still seeking enough proof to formally charge him. This week-long operation is aimed at gathering further evidence.

Radar equipment that can scan beneath ground will reportedly be used.

Brueckner is currently serving a prison sentence for the rape of an elderly woman but is expected to be released soon — a development that has raised serious concerns among those working on the case.