In the European Union the Return Directive aims at establishing common standards and procedures to be applied in Member States for returning illegally staying third-country nationals (Article 1). In part 2 of the serie on crimmigration in the EU this research is focusing on 2 other instruments of the Return Directive: the return decision and the detention.As defined in Article 3 (4) a return decision "means an administrative or judicial decision or act, stating or declaring the stay of a thirdcountry national to be illegal and imposing or stating an obligation to return." According to Article 6 of the Return Directive Member States are obliged to issue a return decision to any third-country national staying illegally in their territory, unless an express derogation is foreseen by Union Law.As studies have showed in some countries of nationality there is for the illegal third-country national, who is expelled by EU Member States, a risk of criminalization in the form of criminal sanctions such as fines and detention. This is the situation when these countries of nationality criminalize emigration. Forced to return immediately to their countries of departure or nationality, these "inadmissibles" never fully become immigrants. I label this as double crimmigrations. These failed migrants become at least suspect citizens and they risk a form of double crimmigration in their countries of departure or nationality as they risk to be penalized twice: firstly by their involuntary return and secondly by the instigation of ciminal proceedings against them in the country of nationality. Double crimmigration should become a topic in EU return policy and security policy in which the EU should also formulate solutions.