Internal Audit

An audit performed by a person (or persons) employed by the firm being audited.

Investopedia Says:
Internal audits have quickly become an important aspect of corporate governance, thanks mainly to the Sarbanes-Oxley Act of 2002.

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Audit where the auditor is an employee of the company. It is generally used to ensure that employees are following the company's accounting policies, but not to determine the fairness of financial presentation, as would an External Audit.

An inspection and verification of the financial records of a company or firm by a member of its own staff to determine the accuracy and acceptability of its accounting practices.