The objective was to evaluate the assistance to people with mental disorders in conflict with the law. It is an evaluation study carried out in two stages Methodological Study and Case Study. The methodological study, developed in February 2019, outlines a construction and validation of the logical model and the matrix of criteria for assessing assistance to the studied group, based on the three procedures suggested by Pasquali's psychometric framework 1) theoristscomposed of theoretical essay, scope review and availability study, in order to identify the contents that make up the logical model and the criteria matrix; 2) empirical - understand the construction of a collection instrument using Google Forms and the selection of 44 specialists for the validation process of the analyzed evaluation instrument; and 3) analytical - carried out using two Delphi steps, in which the item evaluated as adequate is considered valid, which recovered 70% of agreement between the specialists. The case study took place at the Hospital of Custody and Psychiatric Treatment of the State of Rio Grande do Norte. In January 2020, three managers and seven health professionals who worked in the surveyed scenario were interviewed. The textual content resulting from the interviews was subjected to lexicographic textual analysis, with the aid of the software Interface de R pour Analyzes Multidimensionnelles de Textes et de Questionneires and the data analysis was performed from the relevant literature. The theoretical essay reflected on the existence of (in) visible walls that surround people with mental disorders in conflict with the law. The scoping review identified that research on mental health care offered to interns at the Institutes of Forensic Psychiatry in Brazil was predominantly dissertations, with a qualitative approach, in the area of Psychology and Law, published in 2014, carried out in the southeastern region of Brazil, with emphasis on the speeches of health professionals and without specifying the methodology of data analysis. In addition, he indicated that the assistance offered to the interns of these institutions has a punitive character, is based on excessive medicalization and diverges from the current legislation, which hinders the social reintegration of these subjects. The evaluability study resulted in the elaboration and agreement of the logical model; in the analysis and comparison between the reality of politics and the logical model; and in the elaboration of the criteria matrix. The logical model was validated by the Nominal Group Technique. The content adequacy of the criteria matrix was assessed by 16 experts in the Delphi 1 stage and by 12 in the Delphi 2 stage. The content matrix had its content validated by 0.93 Content Validity Coefficient. For managers and health professionals interviewed in the field stage, assistance in the scenario studied is permeated by structural deficiencies, but changes in the scope of institutional management have allowed advances in the process of deinstitutionalization of inmates. It is recommended to establish achievable goals, as well as the criteria matrix proposed in this study to direct continuous and systematic assessment, capable of focusing on improvements in the assistance provided to this cliente (AU).