Who Investigates Military Crimes? CID, NCIS, AFOSI & CGIS

The agency contacting you can tell you a great deal about what kind of investigation may be underway.

For serious criminal allegations involving service members, the principal investigative agencies are generally:

• Army: Department of the Army Criminal Investigation Division (Army CID)
• Navy: Naval Criminal Investigative Service (NCIS)
• Marine Corps: NCIS for serious crimes, with USMC CID handling other criminal-investigative matters in coordination with NCIS
• Air Force and Space Force: Air Force Office of Special Investigations (AFOSI or OSI)
• Coast Guard: Coast Guard Investigative Service (CGIS)

Military police, Security Forces, civilian law enforcement, the FBI, DCIS, and other federal agencies can also become involved depending on the offense, location, and government interests at issue.

The important question is not just which badge the investigator carries. It is why that agency wants you.

If CID, NCIS, AFOSI/OSI, CGIS, or another criminal-investigative agency has contacted you about your own conduct, wants a statement, has advised you of Article 31 rights, or is asking for access to your phone, you may be at a much more consequential stage than the words “we just need to ask you some questions” suggest.

Why NSLF When Military Investigators Are Building the Record

When CID, NCIS, AFOSI, CGIS, or another military investigative agency opens a case, the investigation does not exist in isolation.

The same facts may later be reviewed by:

• military prosecutors;
• Special Trial Counsel;
• commanders;
• convening authorities;
• military judges;
• administrative boards;
• security-clearance decision-makers; and
• military-record or titling authorities.

That is why we believe the strongest early defense is not built from only one perspective.

National Security Law Firm brings together lawyers who have worked inside the government, prosecuted cases, defended service members, advised commanders, served in senior military leadership, and decided cases from the bench.

Our team includes former military judges, former military prosecutors and defense counsel, a former United States Attorney, senior military officers and commander advisers, federal prosecutors, and attorneys with Department of Defense, intelligence, and national-security experience.

That range of experience matters because different decision-makers look at the same investigation differently.

An investigator may focus on developing evidence.

A prosecutor may ask whether the evidence proves a charge.

A commander may be thinking about discipline, retention, or administrative action.

A military judge may later focus on admissibility, credibility, constitutional protections, and whether the government can actually prove its case.

Our lawyers have worked from each of those perspectives.

That gives us the ability to ask broader questions early:

• What is the investigative agency trying to establish?
• What weaknesses would a former prosecutor see?
• What evidence would an experienced defense lawyer want preserved now?
• How might a commander react even if criminal charges never follow?
• What issues would a former military judge consider important if the case reaches litigation?
• Could the same investigation create a security-clearance, administrative, or military-record problem later?

NSLF is also not limited to one stage of the problem.

Our military practice handles the interconnected proceedings that can grow out of an investigation, including military investigations, court-martial defense, military administrative actions, security-clearance matters, and military titling and investigative-record issues.

That matters because an investigation that does not result in a court-martial can still become an Article 15, GOMOR, separation action, clearance issue, or lasting investigative record.

And significant matters do not have to be viewed through only one lawyer’s lens.

Through NSLF’s Attorney Review Board, attorneys with different military, prosecutorial, defense, judicial, federal, and national-security backgrounds can collaborate on strategy before critical decisions are made.

The government has investigators, prosecutors, commanders, and legal advisers looking at the case from different angles. We believe your defense should be capable of doing the same.

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Who Investigates Crimes in the Army?

For serious Army criminal investigations, the principal agency is the Department of the Army Criminal Investigation Division, commonly called Army CID.

Army CID describes itself as an independent federal law-enforcement agency responsible for felony criminal investigations. Its mission extends beyond ordinary criminal cases to war crimes and terrorism investigations, cybercrime, criminal intelligence, forensic and biometric support, and other significant matters involving Army interests.

An Army CID investigation may involve allegations such as:

• sexual assault or other serious sexual misconduct;
• homicide or aggravated violence;
• significant theft or property crimes;
• drug distribution or serious drug offenses;
• fraud;
• domestic violence;
• child abuse;
• cybercrime;
• financial misconduct;
• national-security-related offenses; or
• other felony-level criminal allegations.

Not every disciplinary problem involving a Soldier becomes an Army CID investigation. Military police, commanders, and other Army organizations may address other forms of misconduct.

But if Army CID identifies you as a subject or suspect, requests an interview, asks for access to a device, or advises you of your rights, the matter deserves immediate attention.

Learn what to do if Army CID is investigating you.

Who Investigates Crimes in the Navy?

For major criminal investigations involving Sailors and Department of the Navy interests, the primary federal investigative agency is NCIS—the Naval Criminal Investigative Service.

NCIS states that felony criminal investigations are a cornerstone of its mission and that it is responsible for major criminal investigations involving Navy and Marine Corps equities, service members, and affiliated civilian personnel. NCIS agents investigate offenses under both the UCMJ and federal criminal law where a Department of the Navy nexus exists.

Its criminal-investigation mission includes serious allegations such as homicide, rape and sexual assault, child abuse, robbery, burglary, significant larceny, aggravated assault, and noncombat deaths involving Navy or Marine Corps service members.

NCIS also has major counterintelligence and national-security responsibilities. Within the Department of the Navy, it has specialized authority involving espionage, sabotage, terrorism, and foreign-intelligence threats.

If NCIS wants to speak with you about suspected misconduct, do not assume that the interview is merely an administrative conversation.

See what to do before talking to NCIS.

Who Investigates Crimes in the Marine Corps?

This is where military investigative terminology can become confusing.

NCIS and Marine Corps CID are not the same agency.

NCIS has primary responsibility for serious criminal investigations involving Marine Corps personnel and interests. The Marine Corps also operates its own U.S. Marine Corps Criminal Investigation Division, or USMC CID, within installation Provost Marshal Offices and Marine Corps Police Departments.

The Marine Corps describes USMC CID as a Department of the Navy law-enforcement organization that conducts criminal investigations and other law-enforcement activities in coordination with NCIS. The Marine Corps expressly states that NCIS has primary responsibility for actual, suspected, or alleged serious crimes within the Department of the Navy.

So a Marine may encounter:

USMC CID in one type of criminal investigation,

while a more serious felony allegation may be handled by NCIS.

The agency name matters, but your rights do not depend on whether the investigator’s badge says the acronym you expected.

If the questioning shifts toward your own suspected misconduct, determine your status and understand your rights before assuming you should keep answering.

Who Investigates Crimes in the Air Force and Space Force?

For serious criminal matters involving Airmen, Guardians, or Department of the Air Force interests, the principal agency is the Air Force Office of Special Investigations, formally AFOSI and commonly called OSI.

AFOSI is the Department of the Air Force’s felony-level investigative service. Its official materials identify criminal investigations, counterintelligence, economic crime, cyber matters, and protection against terrorism and espionage among its core responsibilities.

AFOSI investigations can involve allegations such as:

• sexual offenses;
• homicide;
• serious assault;
• robbery and major theft;
• drug use and trafficking;
• fraud involving pay, allowances, contracts, or government funds;
• cybercrime;
• technology compromise;
• espionage; and
• other serious criminal or national-security matters.

The agency’s jurisdiction also extends to matters involving Space Force personnel and resources.

If someone says:

“OSI wants to talk to you,”

they are generally referring to AFOSI.

Learn what to do before speaking with AFOSI/OSI.

Who Investigates Crimes in the Coast Guard?

The Coast Guard’s criminal-investigative agency is the Coast Guard Investigative Service, or CGIS.

CGIS is a federal law-enforcement agency with authority under Title 14 to investigate actual, alleged, or suspected criminal activity. Its special agents can conduct criminal investigations, execute and serve warrants, carry firearms, and make arrests.

CGIS describes its mission as protecting Coast Guard personnel, operations, integrity, and assets through independent criminal investigations. Its workforce includes civilian, active-duty, and Reserve special agents.

A Coast Guardsman facing a serious CGIS investigation can be exposed not only to criminal consequences but also to later NJP, separation, clearance, or other career action.

Learn more about Coast Guard CGIS investigations.

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Army CID and Marine Corps CID Are Different

This deserves emphasis because the shared acronym creates confusion.

Army CID is the Army’s independent federal law-enforcement agency for felony criminal investigations.

USMC CID is a Marine Corps criminal-investigative organization operating through Provost Marshal Offices and Marine Corps Police Departments and coordinating with NCIS.

For Marines, NCIS remains the primary investigative agency for serious crimes.

So if someone tells you only that “CID” is investigating, one of the first questions should be:

Which CID?

That may tell you considerably more about the type and scope of investigation underway.

What About Military Police, Security Forces, and Installation Law Enforcement?

Not every military offense is investigated by a federal special-agent organization.

Installation law-enforcement organizations may conduct initial responses and investigate matters within their jurisdiction. The seriousness and nature of the allegation can determine whether the matter remains with local military law enforcement or moves to CID, NCIS, AFOSI, or another specialized investigative organization.

For example, AFOSI is formally the Air Force’s felony-level investigative service, while Security Forces perform broader installation law-enforcement functions.

Likewise, the Marine Corps has installation-level law-enforcement and USMC CID capabilities even though NCIS maintains primary responsibility for serious Department of the Navy criminal investigations.

The fact that the first person who contacts you is military police rather than a special agent therefore does not necessarily tell you where the case will end.

A report can move from one organization to another as its seriousness, facts, or jurisdiction become clearer.

Can the FBI or Another Federal Agency Investigate a Service Member?

Yes.

Military status does not place a service member outside civilian or federal criminal jurisdiction.

Depending on the alleged conduct, investigations can involve:

• the FBI;
• civilian police or sheriff’s departments;
• a U.S. Attorney’s Office;
• Homeland Security Investigations;
• the Defense Criminal Investigative Service;
• other federal inspectors general or law-enforcement agencies; or
• joint federal, military, state, or local task forces.

DCIS, for example, is the criminal-investigative arm of the defense department’s Inspector General and concentrates on areas such as procurement and acquisition fraud, public corruption, financial crimes, sensitive-technology diversion, cybercrime, and health-care fraud.

Jurisdiction may overlap.

A service member accused of conduct off installation can face both civilian and military scrutiny. A fraud investigation might involve a service investigative agency and DCIS. A national-security investigation could involve military investigators and another federal agency.

For the person under investigation, this can dramatically increase complexity because the investigative system, prosecution system, command system, and clearance system may all be moving at the same time.

What Counts as a “Military Crime”?

The phrase “military crime” is often used broadly, but legally the starting point is usually the Uniform Code of Military Justice.

The UCMJ includes offenses that resemble civilian crimes—such as sexual assault, larceny, assault, homicide, fraud, and certain drug offenses—as well as offenses uniquely connected to military service, including unauthorized absence, desertion, disobedience, dereliction of duty, and conduct unbecoming an officer.

A service member’s conduct may also implicate federal or state criminal law.

Importantly, Article 15 itself is not a criminal offense. Article 15 is the statutory mechanism for nonjudicial punishment. An investigation into alleged misconduct may ultimately result in Article 15/NJP rather than a court-martial, but the underlying misconduct is what is being investigated.

The current Manual for Courts-Martial contains the Rules for Courts-Martial, Military Rules of Evidence, and punitive UCMJ provisions governing this system. The Joint Service Committee identifies the 2024 MCM as the current complete edition and separately maintains later promulgated amendments.

Does the Investigative Agency Decide Whether You Are Guilty?

No.

CID, NCIS, AFOSI, CGIS, and other investigative organizations investigate facts and develop evidence.

They are not courts.

An investigator’s belief is not a conviction.

An investigative report is not a court-martial verdict.

And an allegation being “substantiated” or a person being titled in an investigative record is not necessarily the same thing as being found guilty beyond a reasonable doubt.

For the Defense Criminal Investigative Organizations, DoDI 5505.03 requires investigations and investigative reports to be independent, objective, fact-based, and impartial.

But the evidence investigators develop can later be used by the authorities responsible for deciding whether criminal or administrative action should follow.

That is why how a case is investigated still matters enormously even though the investigator is not the final decision-maker.

Does the Commander Decide Whether You Are Prosecuted?

Not always.

That used to be a much safer shorthand than it is today.

For many ordinary UCMJ offenses, commanders and convening authorities continue to play important roles.

But for designated covered offenses, the military’s Special Trial Counsel system transferred key disposition and referral authority away from the ordinary chain of command. Serious offenses such as murder, sexual assault, domestic violence, kidnapping, stalking, child pornography, and certain other covered misconduct fall within that independent prosecution framework.

This means there are two different questions:

Who investigates the allegation?

and

Who ultimately decides whether and how to prosecute it?

They may be different people in different organizations.

The case may begin with an investigator from CID, NCIS, AFOSI, or CGIS and later be evaluated by Special Trial Counsel, another military prosecutor, a commander, a convening authority, or federal prosecutors depending on the offense and jurisdiction.

If a criminal investigation appears to be moving toward formal charges, our Court-Martial Lawyers handle the case through charging, referral, trial, and appeal.

If Investigators Contact You, Does That Mean You Are a Suspect?

No.

Investigators contact many different people during a case.

You may be:

• a victim;
• a witness;
• someone with relevant records;
• a source;
• a subject; or
• a suspect.

Your status can also change as information develops.

This is why it can be useful to ask:

What is this investigation about?

What do you need from me?

Am I being treated as a witness, subject, or suspect?

Is this interview voluntary?

Are you asking to search anything?

An investigator may not provide every detail. But you should not automatically assume that because an agent sounds informal, your answers have no legal significance.

When Do Article 31 Rights Apply?

Article 31 is one of the major differences between civilian and military criminal investigations.

Under 10 U.S.C. § 831, a person subject to the UCMJ generally may not interrogate or request a statement from an accused or person suspected of an offense without first informing that person of the nature of the accusation, the right not to make a statement regarding the offense, and that any statement may be used as evidence against the person at a court-martial.

Article 31 is not simply “military Miranda.”

The doctrines overlap in purpose, but they arise from different law and do not have identical triggering requirements.

If you are read Article 31 rights, that is an important signal: the questioning concerns an offense of which you are accused or suspected.

Before deciding whether to waive those rights, read our Article 31 Rights Lawyer resource.

What Can Investigators Do During a Military Criminal Investigation?

The exact investigative tools depend on the allegations and lawful authority available.

Investigators may:

• interview witnesses;
• question subjects or suspects;
• collect physical evidence;
• obtain records;
• examine financial information;
• review government systems;
• seek search authorizations or warrants;
• seize and forensically examine electronic devices;
• obtain photographs or video;
• request laboratory testing;
• examine texts, messages, or social-media evidence;
• coordinate with civilian law enforcement;
• consult prosecutors; and
• follow new leads generated during the case.

The investigator contacting you may therefore know significantly more than he or she initially reveals.

This is particularly important during an interview.

You may believe you are simply recounting events from memory while the agent is comparing every answer against witness statements, documents, digital records, or other evidence already collected.

If investigators want your statement, read Should You Talk to Military Investigators? before treating the interview as an ordinary conversation.

What If Investigators Want Your Phone?

A request for your phone can create a separate legal decision from the request for an interview.

Military investigators increasingly rely on digital evidence, which may include messages, photographs, videos, application data, location information, cloud information, metadata, financial information, or other device contents.

There is a critical distinction between:

an investigator asking for your consent

and

an investigator acting under a search warrant, military search authorization, or another lawful basis.

Do not physically interfere with investigators, and never delete, wipe, conceal, or destroy potentially relevant evidence.

But do not assume that being asked to voluntarily consent to a search means you are required to say yes.

The Military Rules of Evidence govern military searches, seizures, consent, probable cause, and potential exclusion of unlawfully obtained evidence.

What Happens After the Investigative Agency Finishes?

A military criminal investigation does not always end in a court-martial.

Depending on the facts, the investigation may be followed by:

• no criminal prosecution;
• additional investigation;
• court-martial charges;
• Article 15/NJP;
• a GOMOR or other reprimand;
• an adverse evaluation;
• administrative separation;
• a Board of Inquiry;
• security-clearance consequences;
• federal prosecution;
• titling or indexing consequences; or
• another personnel or administrative action.

That is why NSLF’s military-investigation practice does not look only at the possible criminal charge.

A case that never reaches a courtroom can still become a career case.

If the investigation turns into a career-threatening administrative action, our Military Administrative Actions Lawyers address the next stage.

If the allegation creates a personnel-security issue, our Security Clearance Lawyers handle that separate process.

If the criminal case closes but an investigative record continues to follow you, our Military Titling Removal practice addresses qualifying investigative-record relief.

Why Knowing the Agency Matters to Your Defense

The same allegation can look different depending on who is investigating it.

An Army CID case may involve an Army command, Army prosecutors, or Army Special Trial Counsel.

An NCIS investigation may involve a Sailor or Marine, Department of the Navy evidence systems, and Navy or Marine Corps military-justice authorities.

An AFOSI case may intersect with Air Force or Space Force command structures, security issues, cyber evidence, or counterintelligence concerns.

A CGIS case may move through the Coast Guard’s distinct military-justice and administrative structure.

A joint federal investigation may create exposure well beyond the UCMJ.

So the defense question is not simply:

“Do I need a military lawyer?”

It is:

“Does my lawyer understand the investigative organization, the offenses it is examining, the evidence it is likely to develop, and the legal systems that may receive that evidence next?”

That is precisely why NSLF’s structure matters.

Our team includes attorneys who have prosecuted, defended, advised commanders, served in senior military leadership, led federal prosecutions, and evaluated evidence from judicial and national-security perspectives.

We defend the investigation you are facing now while planning for the decision-maker who may see the file next.

What Should You Do If CID, NCIS, AFOSI or CGIS Contacts You?

Start by identifying the agency, the agent, and what the person is asking you to do.

Find out whether the request concerns an interview, documents, your phone or computer, another person, or suspected misconduct by you.

Do not lie.

Do not fabricate an explanation.

Do not delete evidence.

Do not pressure witnesses or contact a complainant in a manner that could be viewed as retaliation or interference.

If you are being questioned about your own potential misconduct, determine whether you are being treated as a suspect and whether Article 31 rights apply before making a substantive statement.

If investigators ask for consent to search a device, understand the difference between a request for permission and compulsory legal authority.

And if you have just learned that a criminal investigation exists, consider speaking with counsel before making decisions that become part of the government’s file.

SCHEDULE A FREE CONSULTATION

Online booking is the fastest way to choose a consultation time. You can speak with an attorney, understand your options, and decide whether representation makes sense. There is no obligation to hire the firm.

Frequently Asked Questions

Who investigates Army crimes?

Army CID is the Army’s principal federal investigative agency for felony-level criminal investigations. Military police and other organizations may handle other matters depending on the allegation and jurisdiction.

Who investigates crimes committed by Sailors?

NCIS conducts major criminal investigations involving Navy personnel and Department of the Navy interests.

Who investigates crimes committed by Marines?

NCIS has primary responsibility for serious crimes involving Marine Corps personnel and interests. USMC CID also conducts criminal investigations through Marine Corps installation law-enforcement organizations in coordination with NCIS.

Is Marine Corps CID the same as Army CID?

No. They are distinct organizations. Army CID is the Army’s independent federal law-enforcement agency. USMC CID operates within Marine Corps law enforcement and coordinates with NCIS.

Who investigates Air Force crimes?

AFOSI—commonly called OSI—is the Air Force’s felony-level investigative service.

Who investigates Space Force crimes?

AFOSI conducts serious criminal and related investigations involving Department of the Air Force interests, including Space Force personnel and resources.

Who investigates Coast Guard crimes?

The Coast Guard Investigative Service, or CGIS, conducts independent criminal investigations involving Coast Guard personnel, operations, integrity, and assets.

Can civilian police investigate a service member?

Yes. Military members remain subject to civilian criminal law where jurisdiction exists, and military and civilian law-enforcement agencies can conduct joint or parallel investigations.

Does CID, NCIS, AFOSI or CGIS decide whether I am guilty?

No. Investigators develop evidence. Guilt at a contested criminal trial is determined through the judicial process.

Does the investigator decide whether I am court-martialed?

Not by themselves. Charging and disposition authority depends on the offense and procedural posture and may involve Special Trial Counsel, other military prosecutors, commanders, convening authorities, or federal prosecutors.

If an investigator reads me Article 31 rights, what does that mean?

It generally means you are accused or suspected of an offense about which the questioner wants a statement. Article 31 requires specified warnings before covered interrogation.

Should I talk to investigators if I am innocent?

There is no universal answer. Innocence does not eliminate the risks of an investigative interview. The decision should account for your status, the allegation, the evidence that may already exist, and the consequences of giving or declining a statement.

Can investigators charge me if I refuse to give a statement?

A statement or confession is not required for a case to proceed if other evidence supports further action. Read Can You Be Charged Without Talking to Military Investigators?.

What Does Military Investigation Representation Cost?

National Security Law Firm offers flat-fee representation for many military investigation matters. Fees generally range from approximately $1,000 to $3,500, depending on the nature of the investigation, complexity of the evidence, urgency, and scope of the representation.

The consultation is free and carries no obligation to hire the firm. An attorney can review what is happening, explain whether representation at the current stage may be useful, and identify the applicable fee before you decide how to proceed.

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The Badge Tells You Who Is Investigating. It Does Not Tell You How the Case Will End.

Army CID.

NCIS.

AFOSI.

CGIS.

USMC CID.

Military police.

Security Forces.

Or a federal agency you never expected to hear from.

The name on the badge helps identify who is gathering the evidence.

Your bigger concern is what that evidence can become.

A criminal charge.

An Article 15.

A GOMOR.

A separation proceeding.

A security-clearance problem.

An investigative record that follows you after the case closes.

Or, in some cases, no adverse action at all.

If a military criminal investigator has contacted you about your own conduct, understand your position before you decide what to say, sign, surrender, or consent to.

National Security Law Firm represents service members nationwide and overseas in military investigations and the criminal, administrative, clearance, and records proceedings that can follow.

SCHEDULE A FREE CONSULTATION

Online booking is the quickest and easiest way to reserve a consultation. There is no obligation to retain National Security Law Firm after speaking with us.

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Official Resources

Manual for Courts-Martial, United States — 2024 Edition. The official Manual contains the Rules for Courts-Martial and Military Rules of Evidence governing preliminary inquiries, rights warnings, statements, searches, seizures, and later court-martial proceedings. Read the official 2024 Manual for Courts-Martial

Joint Service Committee on Military Justice — Current Publications and Updates. Because the MCM can be amended after a complete edition is published, the Joint Service Committee maintains the current edition and subsequent updates. Review current MCM publications and amendments

Article 31, UCMJ — Compulsory Self-Incrimination Prohibited. Article 31 establishes military rights protections governing compelled self-incrimination and questioning of accused or suspected service members. Read Article 31, UCMJ

DoDI 5505.03 — Initiation of Investigations by Defense Criminal Investigative Organizations. This instruction addresses the initiation and independence of Defense criminal investigations, relationships with command investigations, investigative reports, and use of investigative information. Read the official investigative instruction

Current Titling and Indexing Instruction — Change Effective July 9, 2026. This instruction governs titling and indexing by military law-enforcement activities, including the credible-information standard and procedures for seeking relief. Read the current titling and indexing instruction

Navy Defense Service Office — Article 31 and Statement Guidance. The Navy’s official Defense Service Office provides practical guidance regarding Article 31 rights, speaking with investigators, consulting counsel, and waiving rights. Read the Navy Defense Service Office guidance

Army Criminal Investigation Division. Army CID is the Army’s independent federal law-enforcement organization responsible for felony criminal investigations and related investigative missions. Visit the official Army CID mission page

Attorney Reviewed By: Katherine O’Brien
Last Reviewed and Updated: September 1, 2026