A civil audit computes tax. A criminal investigation builds a prosecution. The two can involve the same years, the same transactions, even the same underlying facts - and they demand opposite instincts, because conduct that serves you in one can bury you in the other. Telling them apart is therefore a survival skill, and the tells are specific.
Who Is in Front of You
Civil exams are run by revenue agents and tax compliance officers; their credentials say so, their letters carry exam form numbers, and their questions aim at substantiation: prove the deduction, explain the deposit. Criminal investigations are run by IRS Criminal Investigation special agents - the credentials say Special Agent, they typically appear in pairs, and they are required to give you a version of rights warnings. If that introduction ever happens, the proceeding has announced itself: the conversation is evidence, nothing you explain helps, and the only correct response is polite silence and counsel's phone number.
The Transition Tells
Subtler is the civil exam drifting criminal. The classic signs: an active audit that abruptly goes silent, because examiners suspend when fraud gets referred; questions shifting from what happened to why and what you knew, which are intent elements, not tax math; summonses landing on banks and third parties; interviews of employees and associates; a fraud technical advisor surfacing in the correspondence. Any of these in an exam with sensitive facts - unreported cash, false documents, offshore accounts - changes how every subsequent response gets handled.
The Rules Diverge
In a routine civil audit, cooperation within scope is the winning posture. In an eggshell exam - civil on the surface, sensitive underneath - precision becomes everything: nothing false ever gets said or submitted, since lying during an exam is itself a felony; responses stay within the request; and privilege gets managed deliberately, with the attorney as the hub because accountant communications can be compelled. And across both worlds, one constant: voluntary correction before detection remains the most powerful protection in the system. If you cannot tell which proceeding you are in, that itself is the signal to get counsel before your next response. The consultation is privileged from minute one.