A complainant in a case is the person or organization that starts a legal matter by filing a formal complaint or reporting wrongdoing to an authority. The role appears in criminal prosecutions, civil lawsuits, and administrative proceedings, but what the complainant can actually do shifts sharply depending on which of those settings applies. In a criminal case the complainant is usually a witness with limited control. In a civil case the complainant is effectively the plaintiff and runs the litigation.
What a Complainant Is in a Criminal Case
In the criminal system, the complainant is typically the victim of a crime or the person who reports it. That report triggers an investigation, which may lead to a formal criminal complaint filed by a prosecutor or law enforcement officer. The complaint sets out facts showing probable cause that a specific crime occurred and that a particular person likely committed it.1Legal Information Institute. Criminal Complaint A judge reviews it with any supporting affidavits, and if probable cause is found, the complaint is issued and the case moves forward.2Office of the Federal Public Defender. I Was Arrested on a Complaint and Not an Indictment. How Is That Different?
Here is where most people get the law wrong. The complainant does not “press charges” in any legal sense. Once police are involved, the case belongs to the government. The victim becomes a witness for the prosecution, not a party to the case.3United States Department of Justice. Victims and Witnesses The prosecutor alone decides whether to file charges, what to charge, whether to offer a plea, and whether to drop the case. The complainant’s cooperation and testimony matter, but they carry no veto. This plays out most visibly in domestic violence cases, where prosecutors routinely continue with charges even after the complainant asks them to stop.
What a Complainant Is in a Civil Case
A civil case begins when someone files a complaint with a court.4Legal Information Institute. Federal Rules of Civil Procedure Rule 3 – Commencing an Action The person who files is the plaintiff, so “complainant” and “plaintiff” overlap almost completely in civil litigation. “Plaintiff” is the standard term in courtrooms and filings; “complainant” is more common in administrative settings and informal usage.
The civil complaint itself tells the court and the defendant what the dispute is about. It identifies the parties, states the facts, lays out the legal theories, and specifies the relief the plaintiff wants, whether money, an injunction, or something else. A government official prepares a criminal complaint, but a civil complaint is drafted by (or for) the person who feels wronged. The plaintiff drives the case and carries the burden of proof.
Complainants in Agency Proceedings
Not every complaint goes to court. Federal and state agencies handle large numbers of complaints each year through processes that look different from courtroom litigation.
Employment discrimination is a common example. A person who believes an employer discriminated against them based on race, sex, age, disability, or another protected characteristic can file a charge with the Equal Employment Opportunity Commission. The EEOC defines a charge as a signed statement asserting discrimination and asking the agency to act. The filer is the complainant or “charging party,” and the EEOC investigates the allegation rather than leaving the complainant to build a case the way a civil plaintiff would. A charge can also be filed on behalf of someone else to protect that person’s identity.5U.S. Equal Employment Opportunity Commission. Filing a Charge of Discrimination
Housing works similarly. A person who believes they were denied housing or treated unfairly because of a protected characteristic can file a complaint with the U.S. Department of Housing and Urban Development, online, by phone, or by mail.6U.S. Department of Housing and Urban Development. Report Housing Discrimination The agency does much of the investigative work, and an administrative law judge or agency official ultimately decides the outcome.
What Rights a Criminal Complainant Has
Criminal complainants are witnesses rather than parties, but federal law gives crime victims a meaningful set of rights. Under the Crime Victims’ Rights Act, a victim has the right to:
- Reasonable protection from the accused.
- Timely notice of any public court proceeding, parole hearing, or release or escape of the accused.
- Not to be excluded from public court proceedings, unless the court finds the victim’s testimony would be materially altered by hearing others first.
- Be reasonably heard at proceedings involving release, plea, or sentencing.
- Confer with the prosecutor handling the case.
- Full and timely restitution.
- Proceedings free from unreasonable delay.
- Be treated with fairness and respect for the victim’s dignity and privacy.
- Be informed about any plea bargain or deferred prosecution agreement.
Prosecutors and other Department of Justice employees are required to make their best efforts to notify victims of these rights and see that they are honored.7Office of the Law Revision Counsel. 18 U.S. Code 3771 – Crime Victims Rights
The victim impact statement matters more than people realize. At sentencing, the complainant can submit a written statement describing the emotional, physical, and financial harm from the crime. That statement goes into the presentence report the judge reviews. The complainant can also speak at the sentencing hearing itself, or do both.8U.S. Department of Justice. Victim Impact Statements Impact statements do not dictate the sentence, but judges take them seriously, and they are often the only moment in the process where the complainant speaks directly about what happened.
What the Complainant Has to Do
Filing a complaint is not the end of the complainant’s involvement. In a criminal case, the complainant cooperates with investigators, sits for interviews, and typically testifies under oath at trial. Every witness must give an oath or affirmation to testify truthfully before taking the stand.9Legal Information Institute. Federal Rules of Evidence Rule 603 – Oath or Affirmation to Testify Truthfully
In a civil case, the plaintiff must actively build the case. Federal discovery rules require each party to disclose certain information without being asked: people with relevant knowledge, relevant documents and electronic records, a computation of each category of damages with supporting materials, and any insurance that might cover a judgment. Expert witnesses require detailed written reports about their opinions, qualifications, and compensation.10Legal Information Institute. Federal Rules of Civil Procedure Rule 26 – Duty to Disclose; General Provisions Governing Discovery
A civil plaintiff also has an ongoing duty of candor. Every pleading and motion must be signed, and that signature certifies the claims have evidentiary support and are not filed to harass or cause delay. A court can sanction anyone who violates this rule, including an order to pay the other side’s attorney’s fees.11Legal Information Institute. Federal Rules of Civil Procedure Rule 11 – Signing Pleadings, Motions, and Other Papers; Representations to the Court; Sanctions
Can a Complainant Drop the Case
The ability to walk away depends on whether the case is criminal or civil.
In a criminal case, the complainant cannot drop the charges. The case belongs to the government, and only the prosecutor can discontinue it.3United States Department of Justice. Victims and Witnesses A complainant can tell the prosecutor they no longer want to cooperate, and that may influence the decision, but it does not force the prosecutor’s hand. If other evidence supports the charge, prosecution can continue without the complainant’s testimony.
In a civil case, the plaintiff has real power to end things. Before the defendant files an answer, the plaintiff can voluntarily dismiss by filing a notice, and that first dismissal is generally without prejudice, meaning the plaintiff can refile the same claim later. There is a catch: if the plaintiff previously dismissed the same claim in any federal or state court, a second voluntary dismissal operates as a judgment on the merits and permanently bars the claim. After the defendant has answered, the plaintiff needs a court order or a signed agreement from all parties to dismiss.12Legal Information Institute. Federal Rules of Civil Procedure Rule 41 – Dismissal of Actions
Most civil cases that end before trial end in settlement rather than simple withdrawal. A settlement agreement almost always includes a release of claims, in which the plaintiff gives up any right to sue on the same facts again. Once signed, that release bars future recovery on the waived claims, whether they sound in contract, tort, or statute. Releases typically cover only events before the signing date, so new wrongdoing after settlement can still support a fresh claim.
Penalties for Filing a False Complaint
Filing a complaint carries an implicit duty of truthfulness, and the penalties for abuse are real.
On the criminal side, making a false statement to a federal law enforcement officer or agency is a felony under federal law, punishable by up to five years in prison. If the false statement relates to terrorism or certain sex offenses, the maximum rises to eight years.13Office of the Law Revision Counsel. 18 USC 1001 – Statements or Entries Generally At the state level, filing a false police report is typically charged as a misdemeanor, though penalties vary and can escalate for repeat offenders or false reports involving serious felonies.
In civil court, the consequences take a different form. Filing a baseless or frivolous complaint can lead to sanctions, including an order to pay the other side’s reasonable expenses and attorney’s fees for having to respond to claims that lacked evidentiary support or were filed for an improper purpose. There is a built-in safe harbor: if the challenged filing is withdrawn or corrected within 21 days of being served with a sanctions motion, no sanctions are imposed.11Legal Information Institute. Federal Rules of Civil Procedure Rule 11 – Signing Pleadings, Motions, and Other Papers; Representations to the Court; Sanctions
Protection From Retaliation
People sometimes hesitate to file complaints because they fear retaliation, especially at work. Federal law addresses this directly. Every major employment discrimination statute, including Title VII, the Americans with Disabilities Act, and the Age Discrimination in Employment Act, prohibits employers from punishing workers who file discrimination charges, participate in investigations, or serve as witnesses. The EEOC enforces these provisions, and retaliation claims are consistently among the most frequently filed charges with the agency. OSHA separately protects employees who report workplace safety violations. The principle running through all of these laws is the same: filing a legitimate complaint is protected activity, and an employer who fires, demotes, or otherwise punishes someone for doing so creates its own legal liability.