The paper examines the Zetas' operation in the northern state of Coahuila, where people witnessed a severe period of violence between 2010 and 2011. In particular, a large part of the study focuses on Zetas' control of the prison facility in Piedras Negras, Coahuila, which amounted to a situation of "self-government"or "co-government" as labeled by authorities. The level of control exercised by Zetas on the prison was of total control, almost as a "self-contained criminal ecosystem". Outside the prison, the Zetas were also involved in drug trafficking and contraband activities.
In describing this reality, the authors rely on a large number of witnesses, who also testified about the mass execution of forty people in Piedras Negras. In general, the entire local community of Coahuila was asked to be loyal to the Zetas.