Charles H. Rollins | Charles Rollins, PC
September 12, 2026

Parallel construction can hide how the government first obtained a lead in a criminal case. Even thousands of pages of discovery may leave a basic question unanswered: How did investigators know where to look? For a person facing federal charges, that missing history can affect challenges to searches, witness credibility, and the evidence used to build the prosecution’s case.

What is parallel construction in a criminal investigation

One form of this practice is called parallel construction: investigators use an undisclosed lead to develop a second investigative path, then present that path without revealing what started the investigation. Jessica Carmichael’s recent NACDL article describes the problem and offers practical ways to detect it.1 The concern extends naturally to white collar defense, where an unexplained account number, email address, or transaction can direct an otherwise enormous investigation.

Why hidden evidence sources matter in white collar defense

Consider a hypothetical bank fraud case. Agents subpoena a particular account before anything in the disclosed record identifies it. The bank’s response supplies records used to obtain a search warrant. The production contains the subpoena, bank records, and warrant, but nothing explaining how agents selected that account. That gap warrants investigation. It does not, by itself, prove illegal surveillance or misconduct.

The distinction matters because an undisclosed lead, a pretext, and an unconstitutional search are different things. In Whren v. United States, the Supreme Court held that an officer’s ulterior investigative motive does not invalidate an otherwise justified traffic stop supported by probable cause.2 A defense challenge therefore needs more than evidence that officers had an unstated reason to investigate.

But a later warrant does not automatically cure an earlier unlawful search. Murray v. United States requires actual independence: the earlier illegality cannot have prompted the decision to seek the warrant, and information from it cannot have affected the magistrate’s decision to issue the warrant.3 Concealing the first investigative step can prevent counsel from testing precisely those questions.

The missing source may also change the defense on the merits. It could reveal an informant’s incentive to accuse someone, inconsistent accounts, or information pointing toward another participant. Brady and Giglio require disclosure of material favorable evidence, including qualifying impeachment evidence.4 Kyles v. Whitley makes clear that a prosecutor’s responsibilities extend to favorable evidence known to others acting for the government in the case, including police.5 That principle does not make every federal agency’s files automatically discoverable.

How defense counsel can identify parallel construction

Build a chronology showing when each important identifier first appears, which record supplied it, and what investigative step followed. Distinguish the date a document was created from the date investigators received it. Compare subpoena returns, warrant affidavits, interview reports, and available communications between agencies. In a large electronic production, an index organized around those links can be more useful than another broad keyword search.

Look for a targeted request that predates its apparent factual basis, unexplained jumps in location or knowledge, inconsistent descriptions of a source, or references to a separate investigation that never appears in discovery. Carmichael identifies vague source descriptions and unexplained investigative transitions as useful warning signs.6 Treat them as questions to resolve. An omitted report or ordinary referral may explain the gap.

Preserving evidence and requesting criminal discovery

Ask promptly for preservation of the original referral, relevant query logs, communications between participating agencies, recordings, and earlier versions of reports. Specify dates, accounts, devices, and custodians where possible. Preservation is especially important when the final report may differ from the contemporaneous record.

Then explain what the missing information would allow the defense to test. Rule 16(a)(1)(E) provides a route to qualifying documents and data within government possession, custody, or control. Rule 16(a)(2), however, restricts discovery of internal investigative materials and witness statements.7 A request should identify its separate grounds under the discovery rules, constitutional disclosure obligations, and any applicable surveillance statute; merely labeling everything Brady material will not establish entitlement.

Ask the prosecutor to make an informed inquiry of the agencies involved and state the government’s position in writing. If the answer remains incomplete, seek a focused order addressing the particular missing records and why they matter. A demonstrable break in the chronology gives the court a concrete issue to decide.

Challenging unlawful searches and misleading warrant affidavits

A suppression motion should identify the challenged search or surveillance, the defendant’s own protected interest, and the evidence allegedly obtained through the violation. Fourth Amendment rights ordinarily cannot be asserted on someone else’s behalf.8 Filing a motion does not automatically shift every burden to the government or establish a right to a hearing.

If a warrant affidavit misstates the investigation, assess a Franks challenge. A hearing requires a substantial preliminary showing of an intentional or reckless falsehood necessary to probable cause, supported by an offer of proof.9 Material omissions can also matter: the Eleventh Circuit has explained that even intentional or reckless omissions invalidate a warrant only when adding the omitted facts would defeat probable cause.10 The motion should show what a corrected affidavit would say.

If the disputed source is an informant, Roviaro requires a balance between protecting the flow of information and the defendant’s ability to prepare a defense. Disclosure can be required when relevant and helpful to the defense or essential to a fair determination; there is no automatic right to identify every tipster.11 Explain what this source could establish in this case.

Where classified information or FISA surveillance is implicated, identify the governing procedure. CIPA permits court-authorized discovery substitutions or deletions on a sufficient showing. FISA requires notice in specified circumstances involving information obtained or derived from covered surveillance and provides for suppression motions and, under statutory conditions, review by the judge without defense participation.12 Counsel should address those procedures directly and explain why any proposed substitute leaves a material defense question unanswered.

Preserving suppression motions and testing inevitable discovery

Keep track of motion deadlines while pursuing disclosure. Request an extension or permission to supplement when necessary, document late disclosures, and obtain express rulings. Rule 12 allows consideration of an untimely covered motion for good cause; Rule 16 authorizes remedies for discovery violations, including a continuance or exclusion of undisclosed evidence.13 Do not assume an unanswered discovery request preserves a suppression issue.

Expect the government to argue that evidence came from an independent source or would inevitably have been discovered lawfully. Those arguments require factual scrutiny. Under Nix v. Williams, the prosecution must establish inevitable lawful discovery by a preponderance of the evidence; the inquiry rests on verifiable historical facts.14 The chronology should test that claim against what investigators actually knew and were doing.

The practical objective is to make the government’s account testable before the client must make consequential decisions about a plea or trial. Concealment alone does not guarantee suppression or dismissal. It does demand a disciplined inquiry into the source, the legal authority used to obtain it, and the role it played in building the case.

About the author

Charles Rollins is an attorney based in Augusta, Georgia, whose practice includes white collar criminal defense. Learn more about Charles Rollins, PC at the firm’s website.

For questions about representation in a federal criminal investigation, contact Charles Rollins, PC at charles@rollinspc.org or 706-814-2361.

Footnotes

  1. Jessica Carmichael, Parallel Construction: A Defense Attorney’s Guide to Discovering and Challenging Original Source Evidence in Criminal Investigations, The Champion, Mar.–Apr. 2026, at 16. ↩
  2. Whren v. United States, 517 U.S. 806 (1996) (objective justification for a traffic stop despite an ulterior investigative motive). ↩
  3. Murray v. United States, 487 U.S. 533 (1988) (requirements for a warrant search independent of an earlier unlawful entry). ↩
  4. Brady v. Maryland, 373 U.S. 83 (1963); Giglio v. United States, 405 U.S. 150 (1972). These disclosure principles do not create an unrestricted right to the investigative file. ↩
  5. Kyles v. Whitley, 514 U.S. 419 (1995) (prosecutorial responsibility for favorable evidence held by police; cumulative assessment of materiality). ↩
  6. Jessica Carmichael, Parallel Construction: A Defense Attorney’s Guide to Discovering and Challenging Original Source Evidence in Criminal Investigations, The Champion, Mar.–Apr. 2026, at 16, section titled How Does Defense Counsel Identify Parallel Construction in a Case. ↩
  7. Fed. R. Crim. P. 16(a)(1)(E), (a)(2). Disclosure depends on the category sought, the applicable standard, and any governing privilege or court order. ↩
  8. Alderman v. United States, 394 U.S. 165 (1969) (personal nature of Fourth Amendment rights). ↩
  9. Franks v. Delaware, 438 U.S. 154 (1978) (specific allegations, supporting proof, and materiality required for a hearing). ↩
  10. Madiwale v. Savaiko, 117 F.3d 1321 (11th Cir. 1997) (applying the Fourth Amendment omissions standard in a civil action under 42 U.S.C. § 1983). ↩
  11. Roviaro v. United States, 353 U.S. 53 (1957) (disclosure depends on the circumstances and significance of the informer’s evidence). ↩
  12. Classified Information Procedures Act § 4, 18 U.S.C. app. 3; 50 U.S.C. § 1806(c)–(g). The applicable notice and review provisions depend on the collection authority and intended use of the information. ↩
  13. Fed. R. Crim. P. 12(b)(3), (c)–(d), 16(d). Counsel must also consult the scheduling order and applicable local rules. ↩
  14. Nix v. Williams, 467 U.S. 431 (1984); Nix v. Williams, 467 U.S. 431 (1984) (burden of proof and reliance on demonstrated historical facts). ↩