The characteristics that detectives believe are required to be an 'effective detective' were explored in this study. A Repertory Grid Technique and Critical Incident Technique were used to explore in detail the views of experienced detectives (N = 30) from five different police services in Australia and New Zealand about what makes an effective detective. The findings suggest that detectives hold a complex and challenging role that requires 11 key skills. By far, the most important factor was communication skills, particularly how to communicate effectively with a variety of people varying from victims and suspects to colleagues and scientific experts. High levels of motivation and thoroughness closely followed communication as essential skills. The implications of these findings for the recruitment, training and management of detectives are discussed.