As part of a research study undertaken in the period 2003-2011 to understand situations of homicidal violence based in perceptions regarding the act of violence and the surrounding context, we reflect on the meaning of"invisible bourdaries" in the neighborhoods of Medellin (Colombia). Using a qualitative approach that combines documentary sources and interviews, the experiences of 8 participants are analyzed. In the primary results we can see how control over neighborhoods is exercised by different actors through bourdaries not visible to ordinary people. Nevertheless, around these lines people are recruited and controlled and strategies to illegally generate economic resources and to regulate the cultural and social activities of inhabitants are consolidated, thus affecting the social dynamics and imaginary of the neighborhood. In this way, the territories, friendships, and affects of young victims - who are not linked to illegal groups and/or do not have"information" - and of defenseless older adults are controlled.