Four cities were analyzed in term of homicide rates, namely two Brazilian and two Argentinian cities. In each country, a city with high homicide rates and another with low rates were studied over the same three-year period. The theoretical approach of complex systems was used as it examines the link between the local system in its internal interconnections, the influence of the external environment and psychic engagement, namely the interpenetration between the social system and subjectivities. The emphasis of the study and the comparisons were conducted using qualitative research with observation, the use of interviews and focal groups. The results show that in locations with high or low homicide rates, there is synergy between the external environment (macrosocial and macroeconomic politics), the social system (social organization, local government, community participation) and subjectivity, whether it is in the construction of solidarity or social disintegration. Studies about changes in the violent social systems show that persistent and coordinated actions that articulate economic, social and educational investments as measures to prevent and restrain homicides have a positive impact in historical terms.
Homicide; External causes; Violence prevention