Criminal Investigation Procedures and Federal Law
Criminal Investigation Procedures and Federal Law
This domain tests the constitutional and statutory boundaries of a tax investigation: Fourth Amendment searches, Fifth Amendment compelled statements, Sixth Amendment counsel rights, the Service's administrative summons power, parallel Title 18 charges, and limitations periods.
Constitutional limits
- Fourth Amendment: searches need probable cause and a warrant absent an exception - consent, plain view, search incident to arrest, exigency, automobile. Bank records obtained by summons do not require a warrant (United States v. Miller).
- Fifth Amendment: Miranda applies to custodial interrogation. CI interviews are ordinarily non-custodial, but the agent must not create custody by conduct, and any compelled testimonial communication requires immunity under 18 U.S.C. §6002.
- Sixth Amendment: the right to counsel attaches at formal charging; government contact afterward implicates Massiah.
Investigative tools
- §7602 summons must satisfy United States v. Powell: legitimate purpose, relevance, information not already possessed, and compliance with administrative steps.
- §7609 requires notice to the taxpayer for third-party recordkeeper summonses, with a window to petition to quash.
- Statute of limitations (§6531): six years for §7201 evasion; three years for most other offenses, and the period does not begin while no return has been filed.
Worked example
An agent visits a taxpayer's home during a §7201 investigation; the taxpayer says "come in" and, when asked, "go ahead" to reviewing ledgers on the table. Reasoning: entry rests on voluntary consent measured by the totality of circumstances, and scope is what a reasonable person would understand from the exchange (Florida v. Jimeno) - the ledgers were within it, so no warrant was needed. Consent can be withdrawn and does not reach a locked safe the taxpayer declines to open. The agent must avoid any show of force or claim of authority to search, and record the exact words used.
Traps that cost marks
- Treating a §7602 summons as a search needing probable cause.
- Failing to give and document the non-custodial warning, tainting voluntariness.
- Ignoring §7609 notice and the taxpayer's chance to quash.
- Assuming the limitations period runs from the due date when no return was filed.