What Does a Detective/Criminal Investigator Do?

Learn About the Salary, Required Skills, & More

A day in the life of a detective or criminal investigator: Crime scene investigation, Witness interviews, Writing reports, Court room testimony

The Balance / Lara Antal

The real-life job of a police detective or criminal investigator isn't quite as exciting and intriguing as you've seen on TV, but this career definitely has its moments. Unlike patrol officers, detectives spend their days following up on crimes that have already been committed, as opposed to actively patrolling to prevent crime. They also search for and apprehend criminals.

Together with patrol officers, about 807,000 men and women served in this capacity in the U.S. in 2016.

Detective/Criminal Investigator Duties & Responsibilities

Police detectives perform a number of job functions, including:

  • Crime scene investigation
  • Evidence collection
  • Witness interviews
  • Report writing
  • Record keeping
  • Courtroom testimony
  • Preparing arrest warrants
  • Writing probable cause affidavits
  • Preparing and executing search warrants
  • Arresting criminals

Detectives and criminal investigators often specialize in specific crimes, such as crimes against persons, property crimes, homicide, sex crimes, or white-collar crimes.

Detective/Criminal Investigator Salary

Salaries depend greatly on location and agency, as well as how long a detective/investigator has served. Detectives with greater longevity typically earn significantly more than younger workers.

  • Median Annual Salary: $81,920 ($39.38/hour)
  • Top 10% Annual Salary: More than $138,860 ($66.76/hour)
  • Bottom 10% Annual Salary: Less than $43,800 ($21.06/hour)

Source: U.S. Bureau of Labor Statistics, 2018

Education, Training & Certification

Requirements for hiring can vary widely by department.

  • Education: Many agencies require only a high school diploma, while others insist that you have an associate's degree or some college. Some choosier agencies might even require a bachelor's degree. The most common degrees are in criminology and criminal justice,
  • Certification: In addition to any degree requirements, it will be necessary to receive law enforcement certification from your state's standards and training commission, or Peace Officers Standards and Training (P.O.S.T.). The standards for P.O.S.T. certification differ from state to stat, but they generally require a mandated number of hours of academy training and a state certification exam.

Detective/Criminal Investigator Skills & Competencies

You should possess several essential qualities if you're going to succeed at becoming a police detective or criminal investigator.

  • People skills: Detectives and criminal investigators should be able to deal compassionately with people who aren't always on their best behavior. You'll find that you must often deal with grieving families, and you must work closely with other components of law enforcement and the criminal justice system, such as forensic science technicians.
  • Speaking skills: You should feel comfortable speaking with witnesses and suspects. Be prepared to answer questions clearly and concisely.
  • Initiative: You should feel comfortable about taking control of a crime scene and directing investigations and other officers at the scene.
  • Self-control: You must be able to control your emotions as you deal with people suspected of committing violent crimes.

Job Outlook

The U.S. Bureau of Labor Statistics anticipates that employment of police and detectives will increase by about 7% from 2016 through 2026, but areas that will see the most growth are dependent on state and local budgets. It's not likely that every location in the U.S. will see 7% growth.

The demand for police and detectives can also fluctuate yearly as budgets change.

Work Environment

Few careers in criminology are as rewarding or exciting as investigations, but it's equally true that few careers are as stressful. Detectives often respond to gruesome scenes and must confront victims of violent deaths and serious injuries.

Work Schedule

Depending on the agency, criminal investigators might work Monday through Friday, unlike uniformed officers who often work rotating shifts. But crime happens at all hours, so detectives are subject to call-out and they're often required to respond to crime scenes at odd hours.

A criminal investigator can expect to work longer hours at the beginning of a case because it's imperative to gather as much fresh evidence and to track every fresh lead as quickly as possible. It's not uncommon to work up to 20 hours straight or more after initially responding to a crime scene.

How to Get the Job


There are many other degree programs that can help prepare you for a career as an investigator. For example, a political science degree can be very beneficial because it provides a strong foundation for the theory and thinking behind the U.S. Constitution and the evolution of laws.


Police detectives are not entry-level positions. You must go through an extensive hiring process and be hired as a police officer first, then work your way up. Depending on the department, obtaining a position as a detective might be a promotion or lateral transfer. There's usually a requirement that a candidate must serve as a patrol officer for two years or more before being considered for a position as a detective or a criminal investigator.

Comparing Similar Jobs

Some similar jobs and their median annual pay include: 

Source: U.S. Bureau of Labor Statistics, 2018