The Federal Police's 'Missing Persons Cell' investigates thousands of disappearances every year. De Cel was founded at the time of the Dutroux case and will be celebrating its 25th anniversary on 4 September: an ideal moment to dive into their world and look back on that special period together. Who are the people who are looking for all those missing persons, and how do they do it? That is the question Fatma Taspinar asks herself in this four-part series.