Federal Criminal Investigations: Warrants, Subpoenas, and False Statements

Search warrants

A federal magistrate judge issues a search warrant only on probable cause. Fed. R. Crim. P. 41(d) requires an affidavit or other information establishing probable cause to search for and seize a person or property, or to install and use a tracking device. Warrants must describe the place to be searched and the items to be seized; a warrant that fails these requirements can be challenged by a motion to suppress.

Grand jury subpoenas

The grand jury compels documents and testimony by subpoena. Unlike a warrant, a subpoena does not require probable cause; it can be challenged on grounds such as overbreadth, privilege, or the Fifth Amendment act-of-production doctrine.

False statements

A recurring federal charge grows out of the investigation itself: 18 U.S.C. § 1001 makes it a crime to knowingly and willfully falsify, conceal, or cover up a material fact in any matter within the jurisdiction of the executive, legislative, or judicial branch of the United States government. Statements made to agents in interviews are a frequent source of § 1001 charges.

Primary sources

• Fed. R. Crim. P. 41(d) — text of the statute or rule as published by law.cornell.edu (law.cornell.edu). Verbatim: “After receiving an affidavit or other information, a magistrate judge—or if authorized by Rule 41(b), a judge of a state court of record—must issue the warrant if there is probable cause to search for and seize a person or property or to install and use a tracking device.”
• 18 U.S.C. § 1001 — text of the statute or rule as published by law.cornell.edu (law.cornell.edu). Verbatim: “Except as otherwise provided in this section, whoever, in any matter within the jurisdiction of the executive, legislative, or judicial branch of the Government of the United States, knowingly and willfully— (1) falsifies, conceals, or covers up by any trick, scheme, or device a material fact; (2) makes any materially false, fictitious, or fraudulent statement or representation; or (3) makes or uses any false writing or document knowing the same to contain any materially false, fictitious, or fraudulent statement or entry; shall be fined under this title, imprisoned not more than 5 years”

Sources listed above were accessed and verified on August 20, 2026. Statutes and rules are quoted from the linked primary pages as published on that date. Information on this site is general in nature and is not legal advice.

Related reference pages

• Federal Criminal Defense: An Overview of Statutes and Process
• Conspiracy Charges Under 18 U.S.C. § 371
• Federal Drug Crime Prosecutions: Statutes and Process
• Federal Fraud Offenses: Mail Fraud, Wire Fraud, and Related Statutes
• White-Collar Prosecutions: Statutes and Investigative Patterns
• Federal Sentencing: Guidelines, the Presentence Report, and 18 U.S.C. § 3553(a)
• Federal Criminal Trials: Procedure, Speedy Trial, and Burdens
• Plea Agreements in Federal Court: Rule 11 Procedure
• Pretrial Motions in Federal Criminal Cases: Rule 12