Criminal Complaint Example: AO 91 Form, Affidavit, and Filing

A criminal complaint example, in federal practice, is a short sworn document — usually a single page on court form AO 91, with a longer affidavit attached — that names the person accused, cites the statute allegedly violated, states the facts supporting the charge, and is signed under oath before a magistrate judge.¹ Under Rule 3 of the Federal Rules of Criminal Procedure, it must be a written statement of the essential facts of the offense, made under oath before a magistrate.² The document has two jobs at once: it tells the accused what they are charged with, and it gives a judge enough sworn facts to decide whether probable cause exists to issue a warrant or summons.

The Parts Every Criminal Complaint Contains

Federal complaints follow the AO 91 template, and state complaints track the same core elements even when the formatting differs.¹ Five components appear in every one.

Caption and Court Information

The document opens with a header identifying the court, such as “United States District Court for the Eastern District of Virginia.” Below that sits the case caption naming the parties (“United States of America v. John Doe”) and the case number assigned by the clerk. This block is administrative, but it fixes which court has jurisdiction.

Identification of the Defendant

The complaint must name the person being charged. On the AO 91 form, the defendant’s name appears directly beneath the case caption.¹ When a legal name is unknown, a physical description or alias may stand in. The requirement is clarity about who is accused.

Statutory Charges

The complaint identifies the specific law the defendant allegedly violated, both by code section and in plain-language description. On AO 91, this sits in a table with columns for “Code Section” and “Offense Description.” A bank fraud complaint, for instance, cites 18 U.S.C. § 1344 and describes the conduct in everyday terms. Vague accusations will not do; the defendant is entitled to know exactly which law they are alleged to have broken.

Factual Allegations

This is the substantive heart of the document. The form contains a line that reads “This criminal complaint is based on these facts,” usually followed by a checkbox indicating that the details continue on an attached sheet.¹ The facts stated must be specific: when and where the alleged offense occurred, what the defendant is said to have done, and what evidence supports each point. Conclusions and general accusations are not sufficient. The judge needs concrete facts to weigh, and the defendant needs enough detail to begin preparing a response.

Oath and Signature

A criminal complaint has no legal force unless it is sworn. The complainant signs, affirming that the statements are true to the best of their knowledge and belief. A judge or magistrate then signs below the line “Sworn to before me and signed in my presence,” which confirms the oath was administered.² Rule 4.1 allows the oath to be taken by telephone or other reliable electronic means in urgent situations, with the judge recording the testimony and signing remotely.³

How a Federal AO 91 Reads Top to Bottom

The federal form itself is short. Reading it in order, this is what appears:¹

Header line naming the district: “United States District Court for the [District Name].”
Case caption: “United States of America v. [Defendant Name],” with a case number.
Title in bold: “CRIMINAL COMPLAINT.”
Sworn opening: “I, the complainant in this case, state that the following is true to the best of my knowledge and belief.”
A line naming the approximate date, county, and district of the offense, followed by a table of code sections and offense descriptions.
The phrase “This criminal complaint is based on these facts:” followed by either a short summary or a checkbox reading “Continued on the attached sheet.”
Complainant’s signature block, with printed name and title of the law enforcement agent.
Judge’s block: “Sworn to before me and signed in my presence,” with date, city and state, and the judge’s signature and title.

The page itself is skeletal. What gives the complaint its weight is the affidavit stapled behind it.

The Affidavit Behind the Form

The attached affidavit is where the case actually lives. It typically runs through the investigation chronologically: how law enforcement first learned of the alleged offense, what evidence was gathered, what witnesses said, and why the agent believes the named defendant committed the crime. In a straightforward misdemeanor, this attachment might run a page or two. In fraud, drug conspiracy, or complex financial cases, the affidavit can span dozens of pages, sometimes with exhibits.

The level of detail matters because the judge reviewing the complaint is not deciding guilt. The judge is deciding whether the sworn facts add up to probable cause — a reasonable basis to believe a crime was committed and that this person committed it. Probable cause sits well below the “beyond a reasonable doubt” standard used at trial. It demands more than suspicion but far less than proof of guilt. The judge weighs the credibility of the facts, the training and experience of the officer, and whether the pieces together create a fair probability of criminal conduct. If they do, a warrant or summons issues.⁴

Who Signs and Files the Complaint

In federal court, the complainant on the signature line is almost always a law enforcement agent — an FBI, DEA, ATF, or other federal agent who has worked the investigation. Prosecutors from the U.S. Attorney’s office shape the charges and decide whether the evidence is strong enough to file, but the sworn statement comes from the agent with personal knowledge of the case.⁵

Private citizens cannot file federal criminal charges. If you are the victim of a crime, your role is to report it to the appropriate law enforcement agency. The agency investigates, and prosecutors decide whether a complaint is filed.⁵ Some states permit private citizens to swear out a complaint before a magistrate for certain offenses, but even there, a prosecutor retains authority to decline the case.

How a Complaint Compares to an Indictment or Information

A complaint is one of three documents that can start a federal criminal case. An indictment comes from a grand jury after it has reviewed evidence and voted that probable cause exists. An information is filed directly by a prosecutor, usually for misdemeanors or when a felony defendant waives the right to a grand jury. The complaint is the fastest of the three because it needs only a single judge’s review. In felony cases it often serves as a bridge, holding the case together until a grand jury can return an indictment. Once the indictment lands, it supersedes the complaint.⁶

One last distinction worth keeping straight: a criminal complaint is not the same as a police report. A police report is an internal record of what officers observed and found. A criminal complaint is a court filing, sworn under oath, that asks a judge to authorize action against a specific person. A police report may support a complaint, but on its own it does not start a case.

1
U.S. Courts. AO 91 Criminal Complaint Form
2
Legal Information Institute. Federal Rules of Criminal Procedure Rule 3 – The Complaint
3
Legal Information Institute. Federal Rules of Criminal Procedure Rule 4.1 – Complaint, Warrant, or Summons by Telephone or Other Reliable Electronic Means
4
Legal Information Institute. Federal Rules of Criminal Procedure Rule 4 – Arrest Warrant or Summons on a Complaint
5
U.S. Courts. FAQs: Filing a Case
6
Office of the Federal Public Defender. I Was Arrested on a Complaint and Not an Indictment. How Is That Different?