Complainant: Meaning, Definition & Criminology

Instructor: Ken Klamar

I have been a certified police officer since 1993 and have a Bachelor's degree in Criminal Justice Administration. I also have obtained my Master's degree in Criminal Behavior Analysis from the University of Cincinnati.

In this lesson, you will understand what it means to be a complainant in criminal proceedings. You will know the definition of a complainant as it applies to a person and the state.

Complainant Definition

It is the middle of the night, and you are awoken by the sound of glass breaking. You look out the window, and you see the silhouette of a man entering your vehicle parked in the driveway. Not wanting to approach the man, you reach for your phone and call the police.

The police arrive and catch the man in the act of attempting to steal your car. Once the man is in custody, the police will ask you for a detailed statement as to what you saw. You will give the facts that led to you calling the police, and you will have the right to prosecute the man for what he has done.

In the example above, once the phone call was placed to the police, you became a complainant. A complainant is someone who files a report of criminal wrongdoing with the police. The complaint can be supported by oath or in writing, and will detail the facts that led to the complaint. The result is usually the criminal prosecution of another for the alleged crime. In this case, you were the victim of attempted car theft.


A complainant is someone who makes an accusation of wrongdoing. To make an accusation, you are accusing or blaming someone for a crime. As a complainant, you can be the victim of the wrongdoing or merely a witness. In the previous example, let's say that the noise you heard was a person breaking into a convenience store across the street. Calling the police to allege this crime would still make you the complainant, even though you are not the victim.

The complainant plays a crucial role in the prosecution of a defendant. The complainant must be able to provide in specific detail the facts and circumstances that led to calling the police. Without a complainant, the police have much less to work with in prosecution. The complainant, in most cases, can provide details of a crime in progress that the police would not normally have been able to observe. The complainant's knowledge through observation is vital to prosecution at a later date.

Complainant's Role in Criminal Justice

Once a complainant has submitted a sworn statement to police, he will now become an integral part of the prosecution process. In order to swear to a statement, a person must affirm that the facts given in the statement are a true and accurate representation of what happened. A complainant will likely be called to testify to the complaint at a trial or in front of a grand jury. When giving testimony, the complainant will be given an oath by a judge or magistrate to tell the truth regarding facts of the case.

In a trial, the complainant would come face to face with the accused and be subject to cross examination by the defendant's attorney. Cross examination allows the defendant's attorney to ask the complainant questions about the facts and circumstances that may not have been introduced by the prosecution. Often, the defense will try to cast doubt in the judge or jury's minds by way of cross examination.

The state can also be the complainant in a criminal case. Most states have tough domestic violence laws that force the police to make an arrest where there are signs of violence. If a victim of domestic violence does not want to press charges for whatever reason, the state can do so on their behalf. In this instance, the state (or the police) would be the complainant, responsible for the statement detailing the facts of the crime.

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