This article delves into the pivotal role that police encounters play in shaping the experiences of 18- to 25-year-olds who come into contact with the criminal justice system. The study is anchored in an analysis of in-depth narrative interviews with young adults, predominantly young men, in Belfast, Northern Ireland. Their accounts unveil the latent risks of police approaches that may pivot on the ‘age and/or lack of maturity’ of young adults. Introducing the concept of ‘sheriff syndrome’, the research sheds light on the detrimental effects of entrenched, antecedent expectations regarding the behaviours, attitudes and (in)capacity for change of those over the age of 18 years. Participants’ accounts underscore the need for interactions that recognise and protect subjective elements of maturity, while cultivating opportunities for open, respectful and bidirectional communication between suspect populations of young adults and the police.