This paper aims to analyse through a socio-historical perspective how certain crystallized identities are being produced for adolescents sent to Brazil s socio-educational system and their subsequent deadly effects. Emphasizing the knowledge-power psychology, we seek to draw some power lines that make up these constructions. Through the socio-historical analysis, we put into question how the discourses and practices of the so-called psi experts contributes to the production of certain ways of perceiving the poorest segments of the population, building an indissoluble link between crime, violence, poverty and dangerousness. Articulated with others scientific knowledge, these discourses and practices have painted the youth of that segment of society as the new internal enemies of our country. Teens with intrinsic dangerous and incorrigibles tendencies, that needs to be removed from social coexistence in the name of protecting society. A point of view that has contributed to the justification and legitimization of extremely violent approaches to this segment of the population by the state, rather than the implementation of effective social policies.