A4, aimed at combating the impunity of those involved in trafficking women and girls for sexual exploitation, with a focus on enhancing victim protection at the EU’s south-eastern border. Centered on a police-led, cross-border mechanism, A4 fostered collaboration between Austria, Bulgaria, and Greece. It engageed law enforcement agencies (LEAs) to develop tailored tools, strengthened interregional accountability, and promoted victim-centered investigation. The project followed a four-step process: action plan development, LEA capacity-building, pilot testing of a resilient response mechanism, and broad dissemination of results.