The author reviews developments in external oversight internationally and examines the issue of capture in detail using an Australian case study of the Queensland Police Service and the Queensland Criminal Justice Commission (CJC). Capture theory explains peer performance in regulation in terms of techniques by which the group being regulated subverts the impartiality and zealousness of the regulator. The question of capture was assessed by analyzing reports on significant issues involving the CJC and the police. Cases of zealous enforcement of rules were apparent, but the study identified a generally weak approach on the part of the CJC to enforcement and direction. Crucial elements of the CJC's structure and functions exposed it to capture, including a role in facilitating police management, joint operations against organized crime, and reliance on seconded police investigators. Available evidence did not confirm a case of direct capture, but there was evidence from audits of investigations that police involvement in investigations and discipline contributed to a marked attrition of complaints. Weakness in oversight may have also been related to the combined effects of an appeasement strategy, an overly legalistic organizational culture, and inadequate quality control. While examples of zealous and proactive approaches to the control of police conduct were identified, these were outweighed by examples of indecisiveness and inaction and a generally weak approach to ensuring adequate detection, punishment, and prevention of misconduct. Practical measures are recommended to improve accountability that have general application to police oversight bodies. These include a clearer separation between police and the regulator, quality assessment measures, and the exclusion of a facilitation role to allow regulators to focus on police conduct. 45 references and 1 figure