The main purpose of this research is to examine the effects of internal audit reporting lines on fraud risk assessments made by internal auditors when the level of fraud risk varies. Significant emphasis has been placed on the importance of reporting lines in maintaining the autonomy of internal auditors, but the perceived benefits of requiring internal audit to report directly to the audit committee have not been validated or systematically investigated. Results of an experiment involving 172 experienced internal auditors and additional survey findings indicate that internal auditors perceive more personal threats when they report high levels of risk directly to the audit committee, relative to management. Perceived threats lead internal auditors to reduce assessed levels of fraud risk when reporting to the audit committee relative to when reporting to management. This finding runs counter to the anticipated benefits of requirements that the internal audit function report directly to the audit committee, and it reveals potential conflicts of interest and independence threats created by the audit committee itself. We also investigate the effects of fraud risk decomposition on risk assessments made by internal auditors. We find that fraud risk assessment decomposition does not have the same effects on internal auditors as it has on external auditors, and the effects of decomposition do not align with the expected benefits of decomposition.