A special investigation audit is a detailed examination of the financial records of a business, with the primary intent of finding instances of fraud. This procedure is more detailed than a normal audit. The task of the auditor is to gather evidence regarding a fraud, which may also result in acting as an expert witness during subsequent legal proceedings. In a normal audit, the period covered is the financial year just concluded. But in case of Special investigation audit, period covered can be related to many past financial years.