This paper suggests an approach for understanding the conditions under which urban violence emerges in a conjuncture of sharp social inequality and social exclusion and the existing complex relation between crime and poverty. It introduces some considerations about crime institutionalisation in modern society and its relation with cultural patterns of value and of legality that influence both violent behaviours and the mode of controlling criminal offences. The performance of police organisations is considered in relation to the conditions of the state repressive apparatus and the increase in criminality. The empirical analysis is about some criminal offences records for the metropolitan area of Salvador, Bahia, in the nineties, particularly homicide, a type of offence that affects mostly the underprivileged.