The police are key partners in adult protection work locally and take lead responsibility for investigating alleged crimes committed against vulnerable adults in our communities. They therefore play a critical role in many serious and complex adult protection investigations. This paper describes how a large police service has organised its adult protection resources and maps out the basic processes and responsibilities involved in leading criminal investigations involving vulnerable adults. Using a case study it also identifies and examines the different demands criminal work brings at the inter‐agency, agency and case levels and identifies solutions and pointers for best practice.