What is a Detective?

A police detective, also referred to as a criminal investigator, is a sworn law enforcement professional who investigates felony (and sometimes misdemeanor) crimes. Criminal investigators conduct investigations, gather evidence, and build and prepare cases to help ensure prosecutors are able to get a conviction, and often even testify in court themselves.

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These highly skilled law enforcement professionals are called upon to:

  • Evaluate the relevance of concepts, theories and principles to develop different approaches or tactical plans
  • Employ independent judgment
  • Employ resourcefulness
  • Interpret and apply guidelines
  • Apply sound judgment and make effective decisions
  • Act with integrity
  • Work independently or as part of a team
  • Organize and analyze evidence as to draw conclusions from it

Detectives must be able to:

  • Process crime scenes and gather physical evidence
  • Interrogate suspects
  • Interview witnesses and victims
  • Conduct surveillance
  • Prepare formal reports
  • Compile, organize and maintain large quantities of information
  • Use department resources effectively and efficiently
  • Search for evidence in a systematic manner
  • Maintain liaisons with other law enforcement agencies
  • Testify in legal proceedings


The Major Job Duties Performed by Detectives

Researching and Analyzing Crimes – It is quite common for detectives to spend a considerable amount of time researching information regarding the crime they are investigating. This research helps them gain knowledge about the suspects they are investigating and the circumstances surrounding the crime. Once they have successfully gathered the information, they can analyze the facts and piece them together as to best evaluate how they will go about completing the investigative process.

Identifying and Interrogating Suspects – Criminal investigators must, at times, operate as forensic psychologists, getting into the mind of a criminal or ascertaining what type of person would commit a certain crime. This analysis is often accomplished after all evidence is collected and all research is completed. Once an analysis of the crime is made, detectives can better proceed by understanding the type of person for whom they are searching.

Interrogating suspects is a vital aspect of a criminal investigator’s job, as it allows them gather as much evidence as possible, single out a suspect, or even identify a perpetrator.

Testifying in Court – Criminal investigators are often important participants in courtroom proceedings. They may be called to explain evidence or serve as an expert witness, or they may be there to simply shed light on what they believe happened for a crime to have occurred.

Detectives as Law Enforcement Professionals

Detectives beginning their careers working as law enforcement professionals. It is during the initial years as a police officer that the foundation of knowledge of the criminal justice system and of law enforcement is achieved.

To become a police officer, individuals must first ensure they meet the minimum requirements for employment. The majority of police departments, whether at the federal, state, or local level, require individuals to be at least 21 years old; to possess a valid and current driver’s license; and to be a United States citizen.

Many police/sheriff departments do not require any formal education beyond a high school diploma or GED, while other departments require the completion of some type of post-secondary coursework or post-secondary degree, such as an associate’s or bachelor’s degree. These departments often seek candidates who have completed coursework in areas related to law enforcement, such as:

  • Criminal justice
  • Criminology
  • Sociology
  • Forensic psychology
  • Justice administration

Even many police departments that do not require a formal college degree as part of becoming a police officer encourage it, awarding police officer recruits who possess college degrees with educational pay incentives.

Individuals who meet minimum requirements are then required to complete a specific employment process, which typically includes the successful completion of:

  • Written examination/civil service test
  • Physical abilities examination
  • Background investigation
  • Polygraph examination
  • Medical examination
  • Structured panel interview
  • Psychological evaluation
  • Academy training
  • Field training

After working in a patrol capacity for a number of years, upon an endorsement from a supervisor, or upon the completion of a formal college degree (or a combination of two or more of these requirements), individuals may be promoted to a criminal investigator position.

Detectives as Part of Comprehensive Criminal Investigative Teams

Organized criminal investigations bureaus within state patrol agencies, police departments, or sheriff’s offices are typically organized into a number of divisions or units, each of which has its own team of investigators.

Some police departments organize their criminal investigations division into two, main units: Crimes against Persons and Crimes against Property, while other departments have separate units that may be organized in any number of ways.

For example, the Washington D.C. Metropolitan Police Department’s Investigation Services Bureau is organized into the following divisions:

  • Criminal Investigations Division
  • Youth Investigations Division
  • Narcotics and Special Investigations Division
  • Crime Scene Investigations Division

The Birmingham, Alabama, Police Department, on the other hand, organizes its Investigative Operations Bureau into the following divisions:

  • Crimes Against Persons Division
  • Crimes Against Property Division
  • Special Victims Division
  • Vice/Narcotics Division

In general, a detective is assigned to one or more of these organized units, as part of an investigative team. Detectives within specialized teams may work independently or as part of a team, and they may also work alongside patrol officers and with other law enforcement agencies.

As detectives gain more experience in the profession, they may be transferred to larger divisions or units, or they may become unit/division supervisors or leaders.

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