On 3rd April the Robert Schuman Foundation organised a conference on the theme of "The Protection of European Citizens in an Ultra-Connected World" in Luxembourg with the Max Planck Institute. We are continuing the publication of the report with the contributions made by two other participants. Silvio Mascagna, a member of the cabinet of Julian King, European Commissioner for Security explains how the Commission is developing the interoperability of databases in the fight to counter terrorism. Seyda Emek, advisor to the European coordinator for the fight to counter terrorism, Gilles de Kerchove, illustrates the need to retain data to facilitate investigations.