Computer forensic auditing is the process of collecting and analyzing digital evidence from electronic devices. The purpose is to investigate and resolve cases involving cybercrime, fraud, or other illegal or unethical activities. One of the examples is recovering deleted communications and emails, which can help to reveal the identity, motive, or modus operandi of the perpetrators or suspects.

Preventive controls are designed to prevent fraud or errors before they occur. A code of conduct and whistleblower policy signed by all employees annually helps to establish ethical behavior standards and provides a mechanism for reporting unethical behavior, thereby preventing potential fraud. References:
* Institute of Internal Auditors (IIA) Standards on Internal Control and Fraud Prevention.
* COSO Internal Control Framework.

Prior to the commencement of an IT audit, the ability to assess the potential for fraud risk and identifying common types of fraud associated with the engagement is a required competency for internal auditors.
Understanding the specific fraud risks inherent in IT systems and processes is essential for effectively auditing these areas, particularly in detecting and preventing fraud.
IIA ' s Competency Framework for Internal Auditors

The most likely reason the chief audit executive (CAE) decided to conduct a self-assessment with independent validation is that the internal audit activity is relatively small in size and is due for an external assessment. Self-assessment with independent validation (SAIV) is an alternative approach recognized by the IIA for smaller audit functions, where a full external assessment might be impractical or overly burdensome.
This method maintains the quality assurance requirements within the constraints of the organization's size and resources.
Institute of Internal Auditors (IIA) - International Professional Practices Framework (IPPF), Standard 1312 - External Assessments

The scenario describes the internal audit team providing both assurance and consulting services. Initially, the internal audit team was engaged in an assurance activity, verifying the effectiveness of controls through standard audit procedures. However, upon discovering a knowledge gap among employees, the team extended their role to include consulting services by conducting training sessions. This mix of both assurance and consulting in the same engagement characterizes what are commonly referred to as blended services.
Institute of Internal Auditors (IIA) - International Standards for the Professional Practice of Internal Auditing