Article 120 of the Uniform Code of Military Justice (UCMJ), codified at 10 U.S.C. section 920, covers rape, sexual assault, and related sexual offenses. Because these cases often turn on what happened between two people in private, the investigation rarely produces a single decisive piece of proof. Instead, military investigators build a case from many sources: the account of the person reporting, physical and forensic evidence, digital records, and the statements of the accused and any witnesses. Understanding how that evidence is gathered helps explain both how the government proves these cases and where the defense looks for weaknesses.
Which agency investigates
Sexual offense allegations are referred to the military criminal investigative organization for the service involved. The Army uses the Criminal Investigation Division, the Department of the Navy uses the Naval Criminal Investigative Service for both Navy and Marine Corps cases, the Department of the Air Force uses the Office of Special Investigations for Air Force and Space Force cases, and the Coast Guard uses the Coast Guard Investigative Service. These are professional investigative bodies staffed by trained agents, not the accused’s local chain of command, which is meant to keep the inquiry independent of unit leadership.
A second feature unique to the military is the restricted reporting option. A service member who experiences a sexual assault may make a restricted report through a Sexual Assault Response Coordinator or a victim advocate, which allows access to medical care and a forensic examination without triggering a law enforcement investigation. If the person later converts to an unrestricted report, or if someone in the chain learns of the assault independently, the investigation proceeds. This system affects timing and the preservation of evidence in ways that often matter later.
The forensic medical examination
A central source of physical evidence is the sexual assault forensic examination, performed by a specially trained nurse or clinician, sometimes called a SANE or SAFE exam. With the patient’s consent, the examiner documents injuries, collects biological samples such as swabs that may contain DNA, preserves clothing, and records the patient’s account of the event for medical purposes. The resulting collection, often called a kit, is sealed and turned over to investigators.
Forensic evidence can be powerful, but it has limits that experienced investigators and counsel understand. The presence of DNA can show that sexual contact occurred but usually cannot show whether it was consensual, which is frequently the contested issue. The absence of injury does not disprove an assault, and the presence of injury does not prove one, because many lawful and unlawful encounters leave similar or no physical traces. For this reason the medical findings are typically one strand of the case rather than the whole of it.
Statements and interviews
Investigators take detailed statements from the reporting person, the accused, and any witnesses. The interview of the accused is governed by Article 31 of the UCMJ, which requires that a suspect be advised of the nature of the accusation, of the right to remain silent, and that any statement may be used against the accused. These warnings, broader in some respects than civilian Miranda warnings, must be given before questioning a suspect, and a statement taken in violation of Article 31 may be suppressed. The accused also has the right to counsel during a custodial interrogation.
Witness statements help establish a timeline, the level of intoxication of those involved, the nature of any prior relationship, and what people observed before and after the alleged offense. Because intoxication and the capacity to consent are often central under Article 120, investigators pay particular attention to evidence of how much each person had to drink and how each was behaving.
Digital and physical evidence
Modern investigations rely heavily on electronic evidence. Investigators seek text messages, social media exchanges, dating-application records, photographs, location data, and call logs that can corroborate or contradict the competing accounts. Access to a phone or account generally requires consent or proper legal authorization, such as a command authorization for search and seizure or a warrant, and the manner in which devices are seized and searched is a frequent subject of pretrial litigation.
Physical evidence beyond the medical kit can include the scene itself, bedding, surveillance video from common areas, key-card or access records showing movement, and toxicology results. Each of these can place people together, establish timing, or reveal a state of intoxication relevant to consent and capacity.
Chain of custody and reliability
Every item of physical and forensic evidence must be documented from the moment of collection through analysis and storage, so that the government can show it was not altered, contaminated, or confused with another sample. This chain of custody is more than a formality. A gap or error in how a kit was sealed, transported, refrigerated, or logged can give the defense grounds to challenge the reliability and admissibility of the evidence. Defense counsel routinely scrutinize collection procedures, laboratory handling, and documentation for exactly these weaknesses, and the Military Rules of Evidence govern whether challenged evidence comes in.
How the pieces fit together
Because Article 120 cases so often reduce to a dispute about consent or capacity rather than whether contact occurred, no single category of evidence usually decides the matter. The government tries to assemble a consistent picture from the reporting person’s account, corroborating digital and physical evidence, forensic findings, and the behavior of the parties before and after the event. The defense, in turn, looks for inconsistencies among those sources, gaps in the chain of custody, statements taken without proper Article 31 warnings, and innocent explanations for the physical and digital evidence.
For anyone involved in such a case, the practical lesson is that the investigation is wide-ranging and that early decisions, including whether to make a statement, whether to consent to a search of a phone, and whether to seek counsel, can shape the evidence available to both sides. A service member who is questioned as a suspect has the right to remain silent and to consult an attorney, and exercising those rights does not create an inference of guilt. Given the stakes and the complexity of how this evidence is gathered and tested, anyone facing an Article 120 investigation should obtain qualified military defense counsel as early as possible.
Disclaimer
This article is provided strictly for general educational and informational purposes. It is intended to explain how the Uniform Code of Military Justice (UCMJ), the Rules for Courts-Martial, the Military Rules of Evidence, and related military administrative processes work as a matter of public legal education. It does not constitute legal advice, a legal opinion, or a recommendation about any particular case, and it is not a substitute for advice from a qualified military defense attorney who can evaluate the specific facts and command, service, and jurisdictional circumstances involved.
Reading this article, or contacting any website on which it appears, does not create an attorney-client relationship between the reader and any law firm, attorney, or author. Every court-martial, nonjudicial punishment action, administrative separation, and security-clearance matter turns on its own facts, the charged articles, the convening authority, the service branch, and the evidence, and outcomes vary widely from one case to another.
Military law also changes over time. The Military Justice Act of 2016 (effective January 1, 2019) and subsequent National Defense Authorization Acts renumbered and rewrote many punitive articles, revised the Article 32 preliminary hearing, and altered sentencing, clemency, and appellate procedures. Statutes, regulations, executive orders, the Manual for Courts-Martial, and decisions of the service Courts of Criminal Appeals and the Court of Appeals for the Armed Forces may have been amended, superseded, or reinterpreted after this article was written, and article numbers or procedures cited here may have changed.
For these reasons, no reader should act or decline to act based on this content without first consulting a licensed attorney experienced in military justice about their own situation. The author and publisher make no warranty, express or implied, as to the accuracy, completeness, timeliness, or current applicability of the information provided, and disclaim any liability for any action taken or not taken in reliance on it. If you are facing investigation, charges, or an adverse administrative action, time limits may apply, and you should seek qualified counsel promptly.