This article aspires to open a new line of conceptual analysis in the tourism development literature by exploring the relationships between resort development, violent crime and the drug economy. At the centre of our critical realist analysis is the relationship between tourism and transgression, a relationship that we argue deserves a more central place in researching tourism development. A case study of the north coast of Sao Paulo state is reported. Primary data from field observations and interviews are combined with the analysis of published data on crime and violence in the city and media reports of violence. We synthesise a range of academic literatures, published in both English and Portuguese, in the fields of criminology, real estate management, demography, health and tourism studies in order to make our arguments. Utilising retroduction, the mechanism "immunisation" is proposed as having explanatory power in understanding the relationship between tourism resort development, violent crime and the drug economy.