Glossary of Investigation Terms and Definitions

Glossary of investigation terms.
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This glossary of investigation terms is intended to help private investigators, police officers, and everyday citizens understand the meaning of various terms used in investigation work.

During investigation work, private investigators have interactions with police officers to discuss the information contained in police reports. In addition, private eyes work directly with attorneys and lawyers to review court records and discuss court cases. Also, private investigators speak with experts and specialists about forensics, crime scene investigations, and even handwriting analysis.

Understanding these terms and their definitions will help private investigators “speak the language” of their craft. The more well-versed you become in the language of investigations, the more valuable you will become to your clients. It is not your job to replace a qualified attorney, but you should be able to “talk the talk.” To begin, familiarize yourself with all of the definitions in this glossary of investigation terms.

If you’re looking for a handy desk reference book, I recommend Merriam-Webster’s Dictionary of Law, Newest Edition, Trade Paperback, available at It is a comprehensive guide to the language of law for everyone from the homeowner to the legal professional.
It defines more than 10,000 legal words and phrases with clear definitions written in common terminology. Entries include definitions, pronunciations, example phrases and quotations, and additional notes. Also, it features information on the judicial system, important legal cases, government agencies, and historic laws.

Glossary of Investigation Terms and List of Definitions

Following is a list of some of the most common terms and definitions.


Adultery is voluntary sexual intercourse between a married person and another person who is not their spouse. In most cases, only the married party is said to have committed adultery. However, if both parties are married (but not to each other), they have committed separate acts of adultery. Also, adultery is known as Extramarital sex, philandering, infidelity, or cheating. In addition to cheating, other slang terms include creeping, “on the down-low,” sleeping around, and others.


  • An Affidavit is a sworn written statement, voluntarily made under oath or affirmation, confirming the truthfulness of the facts presented. Typically used as evidence in legal proceedings, it carries legal weight and subjects the affiant to penalties for perjury if found to contain false information.

Arrest Warrants

  • Arrests and Arrest Warrants – An arrest warrant is a legal document issued by a court or magistrate authorizing law enforcement to arrest a specific individual. It is based on probable cause, outlining the charges and providing the legal basis for the arrest. Execution of the warrant allows authorities to detain the individual named in the document.

Assault and Battery

  • Assault and Battery – Assault is the intentional act causing fear of imminent harm or unwanted physical contact. Battery involves the actual intentional physical contact, resulting in harm or injury. Together, they constitute a criminal offense, with assault being the threat and battery being the actual act of physical harm, requiring intent and awareness.


A bond is a written, binding agreement to perform something as specified. Various types of bonds appear in marriage, land, and court records used by genealogists. Historically, laws required administrators and executors of estates, grooms, and guardians of minors to post bonds.  If a bondsman failed to perform, the court may have demanded payment of a specified sum as a penalty.

There is likely to be a bail bond associated with every fugitive you are hired to track and retrieve. In addition, detectives need a bond as a part of the licensing requirements in most, if not every, state. In this situation, it is insurance for a third party, such as the state where the private eye has a license. It ensures that the licensed individual properly complies with state laws, statutes, and rules and regulations of their trade.

The cost of obtaining a bond varies from state to state, term periods, coverage amounts, and whether you are an individual or a full-service agency. For more information, see Bail Bonds.


Burglary is the illegal entry into a building or home to commit an offense or crime. Usually, the offense committed during a burglary is the theft of property. Individuals burglarize homes, cars, businesses, storage units, and more. The crime of burglary consists of two elements: trespass and breaking. Often, thieves sell stolen items at pawn shops or via online marketplaces such as eBay.

The trespass element indicates the individual’s presence on the property (car, storage unit, etc.) without the owner’s consent. The breaking element consists of making an opening to enter the building. To commit a burglary is to burgle or to burglarize. Other common names for burglary include Breaking, Housebreaking, Break-in, and Home invasion. The punishment for burglary is usually imprisonment. The term of imprisonment depends on the degree of severity of the burglary. For example, more significant penalties are given if the burglary involves deadly weapons or if anyone is injured due to the crime.

Class Action Lawsuit

A class-action lawsuit involves a large group collectively suing defendants. Common in pharmaceuticals and stock trading cases, they consolidate individual claims for efficiency. While offering advantages to plaintiffs, the compensation for individuals is typically small, with legal teams benefiting more. The claims process is often confusing and laborious, deterring some from participating. Despite potential benefits, the distribution of compensation raises ethical concerns.


A conspiracy is an agreement between two or more individuals to commit a future unlawful act. This entails a joint effort to plan and potentially execute a crime. An overt act, like purchasing supplies or scoping the location, may be necessary to advance the conspiracy. In many jurisdictions, no specific steps need to be taken for the plan to be considered unlawful. The number of participants can vary, involving as few as two individuals or extending to organized gangs, entire organizations, or even military groups. The scope of conspiracies encompasses a broad spectrum of criminal activities.

Copyright infringement (or copyright violation) is the unauthorized use of material covered by copyright law, in a manner that violates one of the copyright owner’s exclusive rights, such as the right to reproduce or perform the copyrighted work, or to make derivative works. For electronic and audio-visual media, unauthorized reproduction and distribution are occasionally called piracy. If you need to research copyright laws, the best place to start is the U.S. Copyright Office. The U.S. Copyright Office website is an excellent resource for learning and understanding copyrighting and related laws.


Crime is the breach or breaking of one or more rules or laws that some governing authority deems unlawful. While every crime violates the law, not every violation counts as a crime. For example, breach of contract and other civil law may rank as “offenses” or “infractions” but are not considered a crime.

Crime usually includes activities considered harmful to the general population or the state, including crimes that cause serious loss or damage to individuals.


Criminology involves the study of crime related to individuals and society. The research also includes social and governmental regulations and reactions to crime. A criminologist is someone who studies crime. Criminologists often work for law enforcement agencies or departments. They work with historical data and information to analyze the behavior and methods used by criminals. Criminologists attempt to identify patterns, trends, and motives to increase the likelihood of apprehending criminals.

Defendants on Plaintiffs

Defendants and Plaintiffs – A defendant is an individual or entity accused or sued in a legal proceeding, defending against allegations. A plaintiff is a party initiating a lawsuit, making legal claims against the defendant, and seeking a legal remedy or judgment. The defendant responds to the plaintiff’s allegations in the legal process.


Detention is keeping a person arrested in a jail cell, prison, or another detention center before their legal trial or sentencing. Such buildings are often referred to as detention centers or detention facilities. People can also be detained illegally or against their will. In this situation, crimes such as kidnapping or unlawful arrest may occur.


Divorce is a legal process that dissolves the marital union between two individuals, terminating their marriage. It involves the formal legal judgment by a court, ending the marital relationship, and outlining the rights and responsibilities of each party. Issues addressed in a divorce may include division of assets, spousal support, child custody, and visitation rights. The process typically requires filing a petition, followed by court proceedings to reach a final judgment. Divorce laws vary by jurisdiction, and the legal framework aims to provide a fair and equitable resolution of marital matters while addressing the well-being of any involved children. Learn about Divorce Investigations.


Embezzlement is dishonestly taking financial assets from another in a manner designed to conceal the activity and avoid detection.


Espionage is the clandestine practice of gathering, transmitting, or obtaining information considered confidential or sensitive, often involving national security. It encompasses activities such as spying, covertly collecting intelligence, and unauthorized disclosure of classified information. Espionage is a serious offense, typically prosecuted under national security laws.


Definition of extortion is a criminal offense that occurs when a person uses coercion to unlawfully obtain either money, property, or services from a person, entity, or institution. It is a crime that organized crime groups commonly practice. If the act is committed using a  computer system, phone, mail, or any instrument of “interstate commerce,” then it is a federal crime.

False imprisonment

False imprisonment is a tort, and possibly a crime, where another person or persons intentionally confine a person or multiple persons without legal authority. It entails the restraint of an individual or the obstruction of their freedom without their consent. The imprisonment of another can take many forms, such as being locked in a room or car, tied to a chair, etc.

The elements of false imprisonment usually involve:

  • The person detained is being held against their will
  • The imprisoned person is unable to move about freely
  • Proof can be provided that the imprisonment was not lawful

Although punishment may vary from country to country and even state to state, it is generally considered to be a 3rd-degree felony, which carries penalties such as up to five years in jail, a fine of up to $5,000, probation, community service, other penalties as defined by the court. If false imprisonment can be proved, damages may be awarded in civil court. False arrest is sometimes used concerning false imprisonment, but it has a different meaning.

Under a false arrest, one person arrests another, but the arresting person does not have legal justification or authority. If the arresting person takes the other into custody and restricts their freedom, it also becomes false imprisonment.

Family Law

Family Law – Includes an overview of Alimony, Child Support, and Legal Guardianship.


A felony is a serious crime. Felonies are generally considered to be the most serious type of crime. The term felony originates from English common law, where felonies were originally crimes that involved confiscating a convicted person’s land and goods. Following are examples of some of the more common types of felonies:

  • Automobile theft
  • Arson
  • Assault
  • Burglary
  • Disorderly conduct
  • Domestic violence
  • Child abuse
  • Counterfeiting
  • Drug abuse violations
  • Forgery
  • Grand theft
  • Grand larceny
  • Homicide, murder
  • Kidnapping

The Federal government defines a felony as a crime that involves a potential punishment of one year or longer in prison.

Grand Larceny

Grand larceny is the theft of another’s property (including money) that exceeds a certain value (for example, $500). This distinguishes the crime from petty (or petit) larceny, whose value is below the grand larceny limit. Some states only recognize the crime of larceny but draw the line between a felony (punishable by state prison time) and a misdemeanor (local jail and fine) based on the amount of the money.

Habeas Corpus

Habeus Corpus is a writ that requires a person under arrest to be brought into court before a judge, usually to secure the person’s release from arrest, unless lawful grounds for their arrest can be provided.

Involuntary Manslaughter

Involuntary Manslaughter is defined as the crime of killing another human being unintentionally.

Judges and Juries

Juvenile Delinquency

  • Juvenile Delinquency refers to the involvement of minors, typically aged 10 to 17, in illegal activities. These offenses, committed by youth, violate criminal laws or engage in behaviors considered delinquent. Juvenile justice systems aim to address and rehabilitate rather than punish, recognizing the developmental nature of youth offenses.


  • Kidnapping is the unlawful and intentional abduction or confinement of an individual against their will, often involving force, threats, or deception. It is a serious criminal offense, with penalties varying based on jurisdiction. Kidnapping typically aims to extort, harm, or control the victim for ransom or other illicit motives.


A larceny is a form of theft. Larceny involves the taking and carrying away personal property without the owner’s consent. “petty larceny” and “grand larceny” refer to the value of items taken.


A lawsuit is a civil action brought in a court of law by which a plaintiff. The plaintiff is a party who claims to have incurred loss as a result of a defendant’s actions and demands a legal or equitable remedy. The defendant is required to respond to the plaintiff’s complaint. If the plaintiff is successful, judgment will be given in the plaintiff’s favor, and various court orders may be issued to enforce a right, award damages, or impose a temporary or permanent injunction to prevent an act or compel an act.


Manslaughter is defined as the crime of killing a human being without malice aforethought or otherwise in circumstances not resulting in murder.


A misdemeanor is generally considered a “lesser” or minor criminal act. Misdemeanors are generally punished much less severely than felonies. Many are punished with monetary fines and do not involve a prison sentence or jail time to be served.

The federal government generally considers a crime punishable with incarceration for one year or less to be a misdemeanor. All other crimes are considered to be felonies. Many states also follow this same view of this type of crime. Depending on the jurisdiction, examples of misdemeanors may include:

  • Petty theft, stealing items of low value
  • Prostitution or selling sexual favors
  • Public intoxication or drunkenness
  • Simple assault
  • Disorderly conduct
  • Trespassing
  • Vandalism
  • Drug possession
  • Driving under the influence (DUI)
  • other similar crimes

Misdemeanors are crimes with a maximum punishment of 12 months of incarceration. Incarceration typically occurs in a local jail rather than a state or federal prison facility. In contrast, felons (those who are convicted of committing a felony crime) are usually incarcerated in a state or federal prison. Most often, those convicted of misdemeanors are punished with probation, community service, or part-time imprisonment, served on the weekends, pay a monetary fine, or some combination of each.

Mug Shots

  • Mug Shots are photographs taken by law enforcement authorities of an arrested individual’s face, typically from the front and side. These images serve as visual records for identification purposes in criminal investigations, legal proceedings, and the maintenance of criminal databases. Mug shots document an individual’s appearance at the time of arrest.

Nolo Contendere

Nolo contendere is a Latin legal term that simply stands for “I do not wish to contend.”  Nolo contendere is also referred to as a plea of “no contest” and is often referred to as “pleading nolo.” In criminal court trials, Nolo contendere is a legal plea made by the defendant who does not admit to committing a criminal charge, nor do they dispute the charge.


A paralegal is a term used to describe people who assist lawyers in their legal work. The profession originated as an assistant or secretary who assisted lawyers with legal matters, research, and related matters. Paralegals are not lawyers but generally have considerable knowledge, education, and even certification in legal matters.

  • The government does not authorize paralegals to offer legal services such as those provided by an attorney or lawyer.
  • They are not considered to be officers of the court (i.e., considered a formal part of the legal system)
  • They are not usually subject to government or court-sanctioned rules of conduct.
  • Paralegals usually work under the direct supervision of a lawyer


Perjury is officially defined as the willful act of swearing a false oath or affirmation to tell the truth concerning matters material to a judicial proceeding.  Perjury can be spoken or written but is most commonly committed as part of spoken testimony in a court case.

During court proceedings that involve witnesses, each witness who testifies must swear under oath that they will tell the truth. Oaths are taken during court in front of the judge and often in front of a jury. Witnesses are not forced or coerced to take the oath, but it is required. When witnesses commit perjury, they falsely promise to tell the truth about matters that affect the case’s outcome.

The exact wording of the oath may vary from country to country and even state to state. Following is an example of the typical oath used in the United States: “Do you solemnly swear or affirm that you will tell the truth, the whole truth, and nothing but the truth, so help you, God?” The court bailiff usually swears in the witness, and the witness usually places their hand on a bible as they agree to the oath.

When a person is convicted of perjury, they may face criminal charges in the form of a financial fine or, in more serious cases, may serve jail time. Each state has its laws and penalties regarding this crime.

Petty Larceny

Petty larceny is stealing a small amount of money or items with little value (such as less than $500). Petty larceny is considered a misdemeanor and is usually punishable at maximum with a term in the county jail. States that only use the term “larceny” often treat theft of smaller amounts as a misdemeanor in sentencing.

Probable Cause

Probable cause is the standard by which a police officer has the right to make an arrest, conduct a personal or property search, or obtain an arrest warrant. A police officer must have probable cause to arrest someone. Probable cause is also used to refer to the standard to which a grand jury believes that a crime has been committed.


  • Racketeering involves operating illegal business activities or schemes, typically for profit. This includes bribery, extortion, fraud, and other criminal offenses. Racketeering is often associated with organized crime. Under laws like the RICO Act in the United States, engaging in a pattern of such activities can lead to severe penalties.

Restraining Order

A form of legal injunction that is most commonly used for domestic violence, harassment, stalking, or sexual assault. Each state has some form of domestic violence restraining order law, and many states also have specific laws for stalking and sexual assault. Orders are issued by a state court and may also be referred to as Protection Orders, Orders of Protection, Protection from Abuse Orders, etc.

Search and Seizure

Search and seizure is a legal procedure where a law enforcement officer who suspects a crime has been committed can perform a full visual and physical search of a person’s property and confiscate any relevant evidence.

Search Warrant

  • A Search Warrant is a legal document issued by a court or magistrate authorizing law enforcement to search a specific location for evidence of a crime. It outlines the scope of the search, the items sought, and the legal basis for the search, ensuring constitutional adherence to privacy rights.

Sexual Assault

  • Sexual Assault is any non-consensual sexual contact or behavior inflicted on an individual. It encompasses a range of offenses, including rape, unwanted touching, and coercion. Laws vary by jurisdiction, but generally, sexual assault is a criminal offense with severe legal consequences, aiming to protect individuals from sexual violence.


A crime is a situation where a person offers money or something else of value to incite or induce another to commit a crime with the specific intent that the person solicited to commit the crime. It is convincing someone else to do something illegal.

This can be accomplished in a variety of ways. Other definitions of Solicitation include: To entice or incite to take evil or illegal action; To approach or accost (a person) with an offer of sexual services; To make solicitation or petition for something desired; To approach or to accost someone with an offer of sexual services in return for financial. Situations involving solicitation are most common concerning prostitution. Prostitutes are said to have “solicited” sex.

Stand-Your-Ground and No Duty to Retreat Laws

The highly controversial stand-your-ground law states that a person may use force in self-defense when there is a reasonable belief of a threat without an obligation to try to retreat or get away first. In some stand-your-ground cases, a person may use deadly force in public areas without having a duty to retreat.

Under these legal concepts, a person is justified to use deadly force in certain situations and the “stand your ground” law would be a defense against criminal charges and a civil suit.

The law is designed to protect individuals who feel their life may be in danger. In some situations, some people hesitate to use lethal force to protect themselves for fear of lethal consequences. These laws say that you can use whatever force that you deem necessary at the moment if you feel that your life is in danger. The statutes are also called a “line in the sand” or “no duty to retreat.”

The following states have such laws:

  • Alabama
  • Alaska
  • Arizona
  • California
  • Florida
  • Georgia
  • Illinois
  • Indiana
  • Iowa
  • Kansas
  • Kentucky
  • Louisiana
  • Maine
  • Michigan
  • Mississippi
  • Missouri
  • Montana
  • New Hampshire
  • North Carolina
  • North Dakota
  • Ohio
  • Oklahoma
  • Pennsylvania
  • Rhode Island
  • South Carolina
  • South Dakota
  • Tennessee
  • Texas
  • Utah
  • West Virginia


A statement is a formal account of the facts related to a case. A statement is given by a witness, defendant, or other party related to a case in a court of law.

Statute of Limitations

A legal statute sets forth the maximum period after certain events so that legal proceedings may be initiated based on those events. This means that you may be unable to sue someone in a court of law after a certain time if the limitation has been exceeded. Also, someone may not be prosecuted for a crime after expiration.


Subrogation refers to circumstances in which an insurance company tries to recover expenses for an insurance claim it paid when another party was responsible for the payment of the insurance claim.  Types of subrogation include:

  • Indemnity insurer’s rights
  • Surety’s rights
  • Rights of business creditors
  • Lender’s rights
  • Banker’s rights

Subpoenas and Summons

A summons is a legal document issued by a court that announces that a legal proceeding has been started against the person to whom it is issued.


A suspect is a person who is believed by law enforcement of committing a crime. Police officers and media reporters often use the term suspect incorrectly when referring to the perpetrator (perp) of the crime or criminal offense. The perpetrator (one who perpetrates) is the person who commits the crime.

The perpetrator is the thief, the bank robber, the assailant, the illegal counterfeiter, etc. The distinction between suspect and perpetrator is that the suspect is not known to have committed the offense. The person is only “suspected” to have committed the crime, while the perpetrator is the person who did.


Legal testimony is a form of evidence that is obtained from a witness who makes a solemn statement or declaration of fact. Testimony may be oral or written, and it is usually made by oath or affirmation under penalty of perjury. Unless a witness is testifying as an expert witness, testimony in the form of opinions or inferences is generally limited to those opinions or inferences that are rationally based on the witness’s perceptions and are helpful to a clear understanding of the witness’s testimony.

Expert testimony – Expert witnesses provide their opinions about facts and conclusions within their field.


Theft, in its simplest terms, is stealing. Theft occurs when a person takes or steals property or items that do not belong to them. Theft is often used as an informal term for crimes against property, such as:

  • Burglary, embezzlement, larceny, looting, robbery, shoplifting, fraud, criminal conversion

In some jurisdictions, theft is synonymous with larceny; in others, the crime of theft has replaced that of larceny. Someone who carries out an act or makes a career of theft is known as a thief.


A tort is a wrong that involves a breach of a civil duty owed to someone else. It is differentiated from a crime involving a breach of a duty owed to society in general. The term “tort” is derived from the Latin word “tortum,” which means crooked or something twisted. Nuisance, negligence, defamation, assault, trespass, and property damage are considered torts. Some are also considered to be crimes and are punishable with imprisonment.

The primary goal of this law is to provide the victim with relief from the damages and to serve as an example to deter others from committing this type of crime. In the tort case, the injured person may be sued for monetary damages and an injunction to prevent the tortuous act. In addition, the injured party may recover damages like reasonable medical expenses, pain and suffering, and loss of earnings during that period. Torts can be generally classified into three categories:

  • Intentional – In this case, an act is done intentionally to harm someone. In this situation, the defendant is aware or should have been reasonably aware, that the action or inaction could harm others.
  • Negligent – These usually occur when the defendant’s actions are considered unsafe.
  • Strict Liability – These types of torts generally apply to defective products.

Wire Tapping

  • If you need legal forms related to any of the above, see a full list of legal forms at
  • Also, see our list of Acronyms related to the legal field, law enforcement, and the investigation industry.

If you need more details on anything in this glossary of investigation terms, visit the legal dictionary on

Questions about this Glossary of Investigation Terms

Please comment below if you have any questions about this glossary of investigation terms and definitions.

Michael Kissiah is the owner of Brandy Lane Publishing, LLC, which owns and operates a small portfolio of websites, including Michael created more than 20 years ago after working as a private investigator in the state of Florida. Since that time, he has become an expert at how to find information online and has written over 1000 articles on topics related to the investigation industry. In addition, he is the author of the "Private Investigator Licensing Handbook", available at


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