What Does a Criminal Investigator Do?

Criminal investigators, also called CIs, play an integral role in the justice system. They gather facts and collect evidence to help solve crimes.

Their skills make them well-suited for a wide variety of jobs. They may work for a city or county police department, the state, the FBI or another federal law enforcement agency in the United States. Their roles vary depending on federal, state or local laws.

A crime investigator may also be a specialist, focusing on forensic science or a specific type of crime. Closely related job titles include crime scene investigators (CSIs) and forensic science technicians.

Some investigators track down information on computers, while others spend more time in the field. Criminal investigators use the information they gain through their daily work to prepare criminal complaints and testify in court.

Criminal investigative work often involves nights and weekends. This career is rewarding and satisfying, but it can also be stressful because of the situations investigators encounter at crime scenes.

Interested in how to become a crime scene investigator or criminal investigator? Read on to learn more about what it will take to get there.

$ 50,600 - $ 145,200
$ 83,500
A criminal investigator takes photos at a crime scene
To a criminal investigator, even the smallest piece of evidence matters. (Credit: Hajrudin Hodzic/Shutterstock)

Job Responsibilities

The criminal investigator or crime scene investigator job description can include a wide range of responsibilities:

  • Collect forensic evidence at crime scenes
  • Interview witnesses
  • Analyze evidence and do further research
  • Observe suspects
  • Write detailed case reports, and file and maintain records
  • Obtain warrants and participate in the arrest of suspects
  • Testify in court

How To Become a Criminal Investigator: FAQs

What are the requirements to be a criminal investigator?

Candidates for this job have graduated high school and earned an associate degree in criminal justice or law enforcement. Some have earned a bachelor’s degree.

Community colleges and universities offer programs, which include courses in criminal law, criminal theory and psychology.

Most Cls graduate from a police training academy and work as police officers to gain law enforcement experience. Training academy work typically includes classes, such as suspect apprehension. It also involves hands-on work, such as traffic control, incident reporting and weapons training. Some programs also include a physical fitness component.

Job candidates with the ability to speak more than one language have an advantage.

Investigative work involves a lot of on-the-job training as each case hones knowledge and skills. Some agencies require investigators to earn continuing education credits, but it varies widely.

What other qualifications do I need?

There are different age and training requirements for city, state and federal jobs for detectives and criminal investigators. Most agencies require candidates to:

  • Be 21 years old.
  • Be a United States citizen.
  • Hold a valid driver’s license.
  • Have no felony convictions.

Some agencies will also require specific certifications, a background check, drug testing and a psychological exam.

Employers look for candidates with previous experience, which can include criminal investigation apprenticeships, military service or work as a police officer or correctional officer. That’s why many officers serve on the police force in another capacity before earning a promotion to criminal investigator. (For more information on how to prepare, read How to Become a Police Officer.)

It’s worthwhile to get the perspective of someone who has done the job, such as Donald Martin (see above) and the Coweta County Sheriff’s Office investigator in this video.

How long does it take to become a criminal investigator?

The time it takes to prepare for this role can vary depending on the type of education you pursue, whether you’re seeking a CI role, CSI job or forensic scientist position.

You may choose to seek out entry-level employment or criminal investigation apprenticeships after completing one of a few different training courses or degree programs:

  • Police academy typically takes six months to complete, followed by a probationary period of six months
  • An associate degree takes two years to complete.
  • A bachelor’s degree takes four years to complete.

It’s helpful to look ahead at possible training programs, education options and career paths to understand all of your options.

For instance, you may want to join the police force first, or you may wish to specialize as a forensic scientist. Once you’ve identified a goal, you can pursue the most efficient path to earning the most comprehensive training that will help you achieve your professional goals.

How much do crime scene investigators make?

According to the U.S. Bureau of Labor Statistics, criminal investigators earn a median annual salary of about $84,000. This skews higher than the average earnings for other types of police and detectives. The highest-paying CI jobs can offer six-figure salaries.

What’s the outlook for this profession?

Police and detective employment opportunities are expected to grow 3% from 2021 to 2031, according to the U.S. Bureau of Labor Statistics. This adds up to about 68,500 job openings each year across this broad industry.

There may be fewer openings for criminal investigators specifically, which is why it’s especially important to be prepared with the right training and education to compete in the job market.

What skills and qualities would make someone a good fit for a CI or CSI job?

Beyond education and training, typical crime scene investigator requirements include a variety of qualities and characteristics:

  • Excellent communication skills
  • Strong critical thinking skills
  • Good decision-making skills
  • Empathy and the ability to understand the perspectives of many types of people
  • Trustworthiness and high ethical standards
The bottom line:

For many people working in the profession, a career as a criminal investigator satisfies a sense of adventure plus a desire to help others in the community. Many different agencies need crime-solving skills, so there’s no shortage of possibilities.

But getting to those jobs will require hard work and time to gain experience as a police officer, in many cases.. If you’re up for the task, read more below about training opportunities.

Why Becoming a Criminal Investigator Is Worthwhile

Donald Martin, criminal investigator ambassador, with former student Santiago

Why Becoming a Criminal Investigator Is Worthwhile

Donald Martin got into police work because an officer intervened in his life when he was a teen and challenged him to do better. 

He recognizes what a difference that intervention made, so now he gives back in a different way — by teaching criminal investigators and police officers. 

He says the job isn't much like what you see on TV — "kicking in doors, search warrants, high-speed chases." It's more about getting the details right.

Find out what else he has to say about becoming a criminal investigator.

Criminal Investigator Training in Your Area


Criminal Justice, A.A.

Metropolitan Community College (MO)
Kansas City (149.7 Miles)

A.A.S. Criminal Justice - Police Science

Metropolitan Community College (MO)
Kansas City (149.7 Miles)

Police Science Certificate

Metropolitan Community College (MO)
Kansas City (149.7 Miles)
School logo for Missouri State University - West Plains in West Plains MO

Law Enforcement, A.A.S.

Missouri State University - West Plains
West Plains (214.6 Miles)

Law Enforcement and Homeland Security, A.A.S.

Southeast Community College Area
Lincoln (261.7 Miles)

Criminal Justice - Law Enforcement, A.A.S.

Metropolitan Community College (NE)
Omaha (291.5 Miles)
Dallas College logo

Digital Forensic Analyst Technical Certificate

Dallas College
Dallas (293.9 Miles)
Dallas College logo

Digital Forensics and Private Investigation Certificate

Dallas College
Mesquite (300.2 Miles)
Dallas College logo

Forensic Science Technician Certificate

Dallas College
Mesquite (300.2 Miles)
Dallas College logo

Fire Arson/Investigation Certificate

Dallas College
Dallas (304.2 Miles)
Des Moines Area Community College logo

Criminal Scene Investigator Certificate

Des Moines Area Community College
Ankey (338.2 Miles)
Des Moines Area Community College logo

Digital Forensic Investigation Certificate

Des Moines Area Community College
Ankey (338.2 Miles)