An internal auditor discovered that a former colleague from the internal audit activity now works...

When an internal auditor encounters a situation where a former colleague works in the department being audited, declaring a conflict of interest and handing over the engagement to another auditor is the best way to ensure objectivity. This approach avoids any potential biases that might arise from personal connections and ensures the credibility and integrity of the audit process are maintained.

The IIA’s Standards for the Professional Practice of Internal Auditing and Code of Ethics.