This chapter analyzes a set of corruption and fraud cases related to Department of Homeland Security (DHS) activities and the Office of the Inspector General (OIGs) interventions. The analysis highlights the strategies applied by the OIGs officers in conducting their investigations. This information will reveal other elements to consider when evaluating the effectiveness of the OIGs. The DHS OIGs activities, including statistical accomplishments, significant recommendations, and an active role in systemic problems have greatly contributed to DHS management improvement. However, corruption and fraud may continue to occur not only because of deficiencies still in agency management but because of the lack of integrity of some public officials as well as contractors. The chapter also includes fraud cases very well documented by whistleblowers. The DHS OIG identified a number of issues related to the challenge of building an effective acquisition management infrastructure for contracting activities in the department.