Understanding Giglio and Its Consequences for Law Enforcement Officers

We defend federal and local (Virginia, DC, Maryland) law enforcement officers and supervisors in integrity issues. As you know, integrity is the cornerstone of law enforcement. The public’s trust, the judicial system’s reliability, and the pursuit of justice all depend on the credibility of those sworn to uphold the law. Yet, a single lie or even an omission—on a report, under oath, or in any official or unofficial capacity—can end a career, compromise a case, and permanently tarnish an officer’s reputation. This is especially true under the legal doctrine established in Giglio v. United States (1972), a landmark Supreme Court case that has lasting implications for law enforcement officers today. It leaves little room for even one mistake. When these types of issues arise, we defend law enforcement officers. 

What Is the Giglio Rule?

The Giglio decision mandates that the prosecution must disclose any information that could impeach the credibility of a government witness—including law enforcement officers. If an officer has a known history of dishonesty, bias, or other impeaching conduct, prosecutors are obligated to inform criminal defense attorneys. Failure to do so can violate a defendant’s right to due process and result in overturned convictions.

Put simply, Giglio means that an officer’s credibility isn’t just important—it’s critical. Many prosecutors, when faced with an officer with negative Giglio information to produce will simply drop an otherwise completely good case. 

When a Lie Becomes a Career-Ending Problem

An officer caught in a lie—whether it’s falsifying a report, shading the truth in testimony, or misleading internal affairs—may be placed on a “Brady list,” “Giglio list,” or “Lewis List” by prosecutors. These lists identify officers whose testimony may no longer be considered reliable. Being on such a list can make it nearly impossible to testify in court, which, in turn, can severely restrict an officer’s ability to perform essential duties.

In many federal agencies and departments, officers who become Giglio-impaired are reassigned to non-enforcement roles or face proposed termination. When this happens, the prosecutor may inform the department or federal agency that they will decline to ever use you again as a witness. This frequently will cause a federal agency or department to place the officer on leave and initiate the termination process. A good example of how this can affect an officer came up in the case of Marin v. DHS (2025). In that case, the U.S. Court of Appeals for the Federal Circuit upheld a removal because a U.S. Attorney deemed the federal law enforcement officer to have credibility issues (i.e. Giglio).

And the stain of Giglio doesn’t just disappear—it can follow an officer throughout their career, even across state lines. When seeking a new law enforcement position, you almost always have to allow the new employer access to your old employer’s records.

Examples of Potential Giglio Violations in Action

• An officer falsifies or omits a detail in a report to make probable cause appear stronger in a criminal case.
• An officer is found to have lied during an internal affairs investigation.
• An officer was found to have lied in his tax filings and the department or agency finds out.
• An officer doesn’t lie but omits key details during an investigatory interview.
• An officer withholds key facts during testimony, later discovered through body-worn camera footage.

Each of these actions, if exposed, can render that officer’s future testimony suspect—potentially undermining any case in which they are involved. When this happens, it is commonly the case that the officer will potentially face termination. In some cases, the officer will be fortunate to be assigned to duties which wouldn’t subject the officer to having to testify in court.

How Giglio Can Affect You and Others

The damage extends beyond individual consequences. A single Giglio violation can:

• Cause other officers or supervisors to be forced to testify against you.
• Lead to civil liability for the officer.
• Cause overturned convictions.
• Require closed investigations to be reopened.
• Damage the public’s trust in an entire department.
• Invite civil liability for the agency.
• Harm prosecutorial partnerships and coordination with the federal or local prosecutor’s office.

Protecting Your Credibility: Best Practices

1. Tell the Truth—Always: This may seem basic, but it cannot be overstated. Accuracy and honesty must guide all official conduct. Of course, if there are legal issues involved, it is important to obtain legal advice from an attorney. If there is a criminal issue involved, legal advice before participating in an interview is critical. In some cases, not testifying will be the best course of action.
2. No Omissions: If there is a material fact that is important in a case, but you are not asked about it in an interview, it is often important to disclose it. Not doing so can lead to a large of lack of candor, which is different than a dishonesty charge.
3. Document Everything/Save Data: Meticulous, truthful documentation helps prevent misunderstandings and protects against false accusations. When situations that are unusual arise, it is often important to keep a journal of the actions you took (or other steps) if you know that you will be interviewed later.
4. Own Mistakes Early: If you make an error, report it promptly. Transparency can mitigate long-term damage. Inlack of candor cases, coming forward early can sometimes avoid disciplinary issues. 
5. Understand Departmental and Legal Obligations: Stay educated on your agency’s policies, Brady/Giglio requirements, and ethical expectations. They basically boil down to two things: (1) tell the truth in all situations, and (2) if questioned about an incident, do not leave out important details.  
6. Seek Legal Guidance When in Doubt: If you face a potential credibility issue, consult a law enforcement attorney before proceeding. Disclosures, when criminal issues are at stake, may change how you approach investigative interviews or disciplinary defense.
7. Legal Defense: If accused of dishonesty or lack of candor, it is critical to hire a law enforcement attorney to help defend you. Our lawyers defend law enforcement officers and supervisors in trial (civil service) boards, before police departments, before federal law enforcement agencies, and in front of the Merit Systems Protection Board or in arbitration.

Contact Us

We defend federal law enforcement officers nationwide, in addition to officers in Virginia, DC, and Maryland. Giglio issues must be handled carefully. In a profession built on public trust, even a single lie can dismantle years of honorable service. We defend law enforcement officers who run into Giglio issues. We can be contacted at (703) 668-0070 for a consultation or through our website.