“Minding the gap” in the research on human trafficking for sexual purposes

. Since the signature of the United Nations Trafficking Protocol in December 2000 that human trafficking has been labeled as a transnational, complex criminal phenomenon. However, despite the implementation of international soft law instruments to tackle the phenomenon, human trafficking is constantly evolving by the frequent changes of strategies, routes, types of exploitation and methodologies applied by the criminal networks. This flexibility of the phenomenon does not only difficult the implementation of effective tackling measures, but it also demonstrates to be an obstacle to produce accurate information on the subject (Cusick et al. 2009). Therefore, this paper aims to analyse the implementation of qualitative research on human trafficking for sexual purposes by 1) the identification of the obstacles on the research; 2) the application of an ethical conduct during the research; 3) the problematic of the participative observation method on the sexual exploitation.