Study IRS-CI concepts by doctrine, one paper case at a time: classify the posture (civil or criminal) first, element-match the offense, build proof-method computations that account for nontaxable sources, recognize when grand jury process replaces administrative summonses, and document every step so a reviewer could reconstruct your conclusions.
Criminal Versus Civil Tax Work: Why the Burden and Purpose Differ
IRS Criminal Investigation investigates suspected criminal violations of the Internal Revenue Code and related financial crimes. That differs from a civil audit in burden of proof, required intent, and consequences, so identical facts can lead to very different cases.
IRS-CI describes its mission as investigating potential criminal violations of the Internal Revenue Code and related financial crimes in a way that fosters confidence in the tax system. In practical terms, agents work cases where a possible outcome is referral for federal prosecution, which can carry imprisonment and fines, rather than the assessment and collection of additional tax. Related financial offenses — for example, money laundering conducted alongside tax violations — fall within that scope.
For scenario practice, this distinction changes the question you ask. A civil analysis asks how much tax is owed and whether penalties apply. A criminal analysis asks whether a person willfully violated a known legal duty and whether the evidence proves each element beyond a reasonable doubt. When you review any fact pattern, first classify the posture — civil, criminal, or still undecided — and let that classification drive which evidence you look for next.
Tax Evasion, False Returns, and Related Financial Offenses: Drawing the Lines
Evasion, false returns, and related offenses such as structuring and money laundering have different elements. Element-matching — listing what each offense requires and checking every fact against it — is the core decision-making skill to drill.
Willful tax evasion requires a voluntary, intentional violation of a known legal duty; filing a false return is a separate perjury-type offense with its own elements. A good-faith misunderstanding of the law negates willfulness, which makes reliance on advisers a genuine defense issue. Work a mini-scenario: a return contains inflated deductions and the preparer says the taxpayer supplied the numbers. The tempting conclusion is evasion. The better analysis asks for affirmative acts — concealment, altered records, instructions to the preparer — that show the taxpayer knew the deductions were false.
Related financial offenses shift the analysis again. Structuring focuses on breaking up cash transactions to avoid reporting requirements; money laundering focuses on financial transactions involving proceeds of specified unlawful activity. Neither requires proving the underlying tax was legally owed, so a fact pattern can support a financial charge even while the tax question stays open. Practice labeling each fact pattern with the offense whose elements it actually fits, not the offense that sounds most serious.
Building a Net Worth Schedule That Survives Scrutiny
The net worth method infers income from growth in net worth plus nondeductible expenditures, minus nontaxable sources. Its recurring weakness is unaccounted nontaxable sources such as loans, inheritances, and transfers, so build that check into every schedule.
Courts permit this circumstantial proof of income when the opening net worth is established with reasonable certainty and the investigation is thorough, so a schedule must show both. List identifiable assets and liabilities at the start of the year, note where each figure came from, then compare with year-end. In a worked example: a subject's assets rise $200,000 during the year and living expenses total $60,000, implying $260,000 of receipts. A plausible mistake is treating a $40,000 home-equity loan deposit as income.
The better decision is to identify nontaxable sources before computing any omission: loan proceeds are not income, so unexplained income falls to about $220,000 and the conclusion changes materially. Embezzled funds behave the opposite way — proceeds of illegal activity are taxable income, not a nontaxable source. Write both rules into your notes as a paired check: every dollar entering the computation must be classified as taxable, nontaxable, or a transfer, with a stated reason.
Choosing Among Proof Methods: Specific Items, Bank Deposits, Net Worth, Source and Application
Each proof method fits a different records picture. Specific items need identified transactions, bank deposits fit subjects whose receipts flow through banks, net worth suits hidden income, and source and application suits spending-heavy cases. Match method to records before computing.
Choosing a method is a decision about inference strength and record availability, not preference. Specific items provide the most direct proof but require identified unreported items, so they fit skimming cases where side sales can be traced. Bank deposits work when most receipts flow through accounts, but every internal transfer between the subject's own accounts must be excluded or income is double-counted. Net worth handles concealed income but inherits the nontaxable-source problem described earlier.
Source and application of funds shifts focus from accumulation to spending. It fits a subject whose known income cannot cover observed expenditures. The trap here is different: an expenditure paid from loan proceeds is still an application of funds, but the loan itself is a source that offsets it, so omitting the source overstates unexplained spending. Before any computation, name the method you would use and justify it in one sentence tied to the records described in the fact pattern.
| Method | Best fit | Key inputs | Typical computation trap |
|---|---|---|---|
| Specific items | Identifiable unreported transactions | Direct evidence of each item, tied to a year | Reaching beyond what the evidence actually connects to the year |
| Net worth | Concealed income, scattered records | Opening and closing assets, liabilities, living expenses | Omitting nontaxable sources such as loans or inheritances |
| Bank deposits | Receipts concentrated in bank accounts | Total deposits, transfers, non-income items | Double-counting transfers between the subject's own accounts |
| Source and application of funds | Spending-heavy subjects | Expenditures, known income, funding sources | Counting loan-funded spending without subtracting the loan as a source |
Administrative Summons Versus Grand Jury Process in Parallel Investigations
An administrative summons is a civil investigative tool; once a matter becomes a grand jury investigation, documents generally must come through grand jury process. Scenario answers should recognize which track each request belongs on.
An IRS administrative summons must serve a legitimate purpose, seek relevant information, request material the IRS does not already have, and follow the required administrative steps. When a grand jury is investigating the same taxpayer, using administrative summonses against the target to gather grand jury material is restricted by case law and policy, because the grand jury's own compulsory process and secrecy rules govern. Scenario: an agent, learning that a grand jury has opened an investigation of a business owner, issues an administrative summons to the owner's bank for records.
The plausible mistake is treating the summons as a shortcut around subpoena logistics. The better decision is a grand jury subpoena, because the evidence then sits on the correct procedural track: secrecy obligations are preserved, challenges to an improper summons are avoided, and the criminal case stays clean. This matters because documents gathered on the wrong track can draw motions and delay — and the parallel-proceedings boundary is exactly the kind of judgment a scenario question can test without any arithmetic at all.
Documentation and Agent Authority: What Strong Scenario Answers Show
Scenario answers should demonstrate documentation discipline: dated, sourced figures; contemporaneous notes; clear exhibit references; and verified authority for each investigative step. Identity and authority matter on paper cases just as they do in the field.
A well-documented file lets a reviewer reconstruct every conclusion without asking the writer. That means each computation line names its source, interview notes are dated and attributable, and exhibits are referenced by number rather than described loosely. IRS-CI's public materials echo this theme from the outside: the agency offers a tool for the public to verify that a special agent works for IRS-CI, and notes it is not available during all enforcement actions due to operational and safety considerations. Authority and identity are part of the record.
On paper scenarios, apply this as a checklist rather than drama: identify the legal authority for each step, state what the subject was told and when, and record how evidence moved from collection to storage. Avoid inventing forceful enforcement details; strong answers stay procedural — what was authorized, what was documented, and what a reviewer would need to see. This habit also builds the writing discipline scenario sections reward: short, sourced, and verifiable statements over narrative flourishes.
A Self-Administered Net Worth Exercise, Rubric, and Adaptable Sequence
Build a small net worth schedule from a fresh fact pattern, score it against a four-point rubric, then rotate proof methods weekly. Use the readiness checks below to decide when your concept review is complete.
Exercise: write a one-page fact pattern — for example, $150,000 in asset growth, $50,000 in living expenses, a $30,000 loan, and a $20,000 transfer between the subject's own accounts — then build the schedule yourself. Expected observations: the raw receipts figure implies $200,000, but after removing the loan proceeds and the internal transfer, unexplained income drops to roughly $150,000, and your conclusion should state the method's limitation rather than a precise tax owed. Score the schedule against the rubric below; treat the scores as learning milestones, not predictions.
An adaptable sequence: first block, criminal-versus-civil distinctions and the willfulness standard; second block, the four proof methods, one per session, each with a computed mini-case; third block, summons and grand jury boundaries using two contrasting fact patterns; final block, documentation — rewrite your earlier computations to citation standard. Compress blocks if time is short, but keep one computed case per method. Readiness checks: you can state the willfulness definition unprompted, complete the net worth exercise above in one sitting, select the right method for three different records pictures, and explain why a grand jury subpoena replaces a summons mid-investigation.
- Opening net worth lists every asset and liability with a stated source for each figure.
- Every inflow is classified as taxable, nontaxable, or a transfer, with a one-line reason.
- The final figure is labeled 'unexplained income,' not 'evaded income,' and the method's limits are stated.
- You can justify the chosen proof method in one sentence tied to the records described.
References and further reading
Use these references to explore the concepts and check the latest information from the relevant organizations.