When an internal auditor suspects fraud during an assurance engagement, the first step should be to determine whether any additional audit work needs to be performed. This involves assessing the potential scope and impact of the suspected fraud and deciding on the appropriate audit procedures to confirm or refute the suspicion. This step is crucial to gather sufficient information before taking further actions.
* Option A: Recommending sanctions is premature without confirming the fraud.
* Option C: Launching an investigation is a subsequent step that may require coordination with fraud experts.
* Option D: Requesting immediate remediation is also premature without confirming the fraud.
References:
* IIA Standard 1220: Due Professional Care.
* IIA Practice Guide: Internal Auditing and Fraud.

The primary reason a chief audit executive should dedicate time and resources to the continuing professional development of internal audit staff is to ensure they have the competency to address high-priority risks.
Continuous professional development ensures that audit staff are equipped with up-to-date knowledge and skills necessary to effectively audit complex and evolving risk environments, thereby contributing directly to the effectiveness and reliability of the internal audit function.
IIA standards on continuing professional development and staff competencies.