Intensive scrutiny of tax assessments to detect evasion and prepare prosecution-ready files while preserving evidence. The instruction mandates intensive scrutiny of selected assessments to detect errors and tax evasion, guiding officers to use reputational information, inter office intelligence, abnormal wealth changes, and account irregularities to identify potential prosecution cases. It prescribes investigative steps: review prior profit and wealth records, examine audit and cost auditor notes, obtain wealth statements, and apply trade specific account investigation methods. Where fraud is found, original documents and statutory statements must be preserved, independent evidence collected, expert opinions obtained, witnesses' statements recorded without coercion, counsel consulted, and administrative approval secured before prosecution.