This article aims to explore the driving factors behind the process of crimmigration, the merger of crime control and migration control. By analysing the legal and policy framework governing the so-called ‘Mobile Security Monitor’ – the discretionary immigration checks carried out by the Royal Netherlands Marechaussee in the borderlands with Belgium and Germany, the research explores the extent to which the framework might leave room for crimmigration-based decisions on the street level. As the article shows, the dual nature of the Mobile Security Monitor as both an instrument for immigration control and crime control combined with an important name-change and the ongoing securitization of migration in Europe seem to create a favourable environment for crimmigration.