How to Become a Detective: Full Guide
How to Become a Detective: Full Guide

How to Become a Detective: Full Guide

How to become a detective: Key steps to take

  1. Gain educational proficiency
  2. Enroll in police academy and gain experience
  3. Pursue PI license and gain experience
  4. Take detective test
  5. Apply for advancement or launch your own business

Progression from police officer to the role of police detective requires several years’ experience in law enforcement, a high level of dedication and a wide range of skills including observation, communication and the ability to evaluate evidence.

Police detectives work alongside uniformed police officers to investigate criminal activity.

Their day-to-day role may involve:

  • Collection and evaluation of evidence
  • Interviewing witnesses
  • Identifying potential suspects
  • Obtaining arrest warrants
  • Assessing the overall facts and evidence of a case

Where a police officer may initially attend a crime scene and gather evidence, a police detective further investigates the case.

The salary for a police detective varies depending on seniority and where in the US you work, but the average base salary in 2022 was approximately $76,000.

By comparison, a private detective or investigator is a civilian who holds a private detective license.

A private detective may have previously worked in the police force or another relevant career field.

Their role will generally be to gather information, conduct surveillance, track missing individuals and interview people.

The salary for a private detective varies greatly depending on where you work, what area of crime you specialize in and whether you work for yourself, for an investigative agency or within a larger corporation.

In this article, you will find information on how to become a police detective or private detective, details of the detective role and a list of frequently asked questions about detective work.

What Is Required to Become a Police Detective?

So, how do you become a police detective?

It’s important to note that the exact requirements for how to become a police detective vary depending on which US state you wish to work in.

For example, the specific requirements for how to become a NYPD detective could differ from the requirements for the LAPD.

However, these are the conditions you will generally be expected to meet:

Background, Personality and Skills

Working as a detective requires a particular set of skills and personal attributes beyond those needed to work as a police officer.

These include:

  • Inquisitiveness
  • Empathy
  • Investigative skills
  • Good communication, whether written, verbal or non-verbal
  • Decision-making
  • Resourcefulness
  • Patience
  • Writing skills
  • The ability to assess diverse and numerous pieces of information
  • Problem solving and critical thinking
  • Attention to detail
  • Emotional intelligence
  • Situational judgement

You must also pass background screening checks and have a clean criminal record.


The educational requirements to work as a detective vary between US states, but the minimum for many police departments is a high school diploma/college degree or GED.

However, the higher your level of education, the higher your chances of landing a police detective role will be.

Ideally, you will achieve an associate degree or higher in a relevant subject.

As a working police officer seeking promotion, you will also have received occupational training.

For many states, working as a detective requires that you first pass a detective test, such as the National Detective/Investigator Test (NDIT) or the Police Detective (PDET) test.

This will lead to certification as a detective.

Relevant Experience

To work as a police detective, you must have work experience in law enforcement agencies.

This is why most police detectives start out as police officers. You will be expected to have several years of investigative experience.

Depending on the US state, the length of relevant experience required before you can apply for a detective role ranges from two to five years.

What Is Required to Become a Private Detective?

The requirements for how to become a private detective vary between US states but experience of law enforcement is generally required to obtain a license of practice.

You may also need firearms training. Background checks will be carried out, including whether you have any criminal convictions or not.

You must be over 18 years of age, a US citizen and deemed mentally competent to work as a private detective by a US court.

How to Become a Detective: Key Steps to Take

If you decide on a career as a detective, whether that is a police or private detective, there are a number of key steps you should take.

Step 1. Gain Educational Proficiency

A good level of education is required to ensure that a detective has sufficient math and literacy skills to carry out their jobs effectively.

A high school diploma or GED is the minimum educational qualification required to work as a detective.

However, an increasing number of police departments ask that their detectives have a degree in a relevant subject in addition to police training.

As a private detective, a bachelor’s degree can also be helpful and is a requirement in certain US states before you can obtain a license of practice.

Examples of relevant degree programs include:

  • Criminal justice
  • Criminology
  • Sociology
  • Law
  • Forensics/Computer forensics
  • Law enforcement
  • Criminal law

Step 2. Enroll in Police Academy and Gain Experience

If you want to progress to a police detective role, your next step should be to enroll in a training academy once you have passed any entry exams.

The minimum requirements for a police academy generally include the following:

  • US citizenship
  • Minimum age of 18 years
  • Driver’s license
  • No criminal record
  • High school education

Requirements vary between US states and higher levels of education may be needed for certain establishments.

You will spend between six and eight months at a police academy and train across a range of areas such as ethics, self-defense, first aid and firearm use, report writing and physical fitness.

Should you successfully graduate from a police academy you will have the option of employment as a police officer and be involved in real criminal cases.

You will generally transition from the academy to life as a police officer by going through a field training program with a senior officer.

After this probationary period, most police officers will be expected to choose an area of specialization.

The timelines for this probationary period may vary depending on the US state.

Key to how to become a police detective is having sufficient law enforcement experience.

The required number of years’ experience varies between US states and police departments but may be as little as three years.

Step 3. Pursue PI License and Gain Experience

If you want to work as a private detective or investigator, you will generally be required to have law enforcement experience before you can obtain your license of practice.

The full requirements for how to become a private detective and obtain licensure vary between US states but are likely to include:

  • A minimum age limit of 18 years
  • No criminal convictions
  • Relevant law enforcement experience and/or experience as a civilian investigator
  • At least high school education but more likely a relevant degree
  • That you pass a private detective test

Many private detectives obtain law enforcement training and experience by enrolling in a police academy and spending several years as a police officer.

Alternatively, a military background can prove useful if you’re wondering how to become a detective without being a police officer.

Holding a relevant degree may reduce the amount of experience that is required to obtain a private detective license.

How to Become a Detective: Full Guide
How to Become a Detective: Full Guide

Step 4. Take Detective Test

To qualify as a police detective, you will generally take either the National Detective/Investigator Test (NDIT) or the Police Detective test (PDET).

The NDIT is a 75-question exam that assesses your knowledge of criminal investigations, court cases and investigative interviewing.

The PDET is a 100-question test that assesses your knowledge of police investigative procedures, laws related to police work and how to complete reports.

To obtain licensure as a private detective, the test you take will depend on the US state you wish to be licensed by/work in and the area of investigation you wish to specialize in.

For instance, private detectives who specialize in negligence or criminal defense investigation will generally seek Certified Legal Investigator (CLI) status.

This test and license are offered by the National Association of Legal Investigators (NALI).

Requirements for this license include:

  • A minimum 70 percent score on the test
  • Five years of full-time, relevant experience or acceptable academic coursework
  • The completion of a 1,000-word research paper

Private detectives specializing in security must seek certification as a Professional Certified Investigator (PCI). This is provided by ASIS International.

Requirements for this license include:

  • High school diploma
  • Five years’ investigative experience, including two years’ experience of case management
  • Passing the 140-question test

Step 5. Apply for Advancement or Launch Your Own Business

Once you have passed your police detective test, there are several steps you can take to improve your chances of progressing to a detective role:

  • Check that you meet all the requirements to be a police detective in both the police department and the US state where you work. Do you need additional qualifications, for instance, or more experience in a particular field of policing?
  • Attend a large police academy if you initially attended a small, local police academy.
  • Pay attention to the detectives you work with. What can you learn from them?
  • Consider whether your chances would be improved by gaining additional qualifications, such as a relevant degree.
  • Gain experience in the areas of policing that will benefit your work as a detective. Two key areas are interviewing and interrogation.
  • Tell your superior officer that you are interested in promotion to a detective role and ask for their advice on improving your chances.
  • Stay aware of any detective openings within your own police department or, if you are willing to move, in another police department. Generally, the larger a police department is, the more detective opportunities there are likely to be.

Check what the detective application process is within your police department and once a relevant opening appears, go for it.

Once you have passed your private detective test and obtained a license, there are several options open to you.

You could start your own business, apply to work for a detective agency or look for an investigator role within a large corporation.

The idea of running your own business may be appealing but you will generally need several years’ experience of working as a private investigator before you can set up your own detective business.

Therefore, the best step to take after becoming licensed is to seek work at a detective agency or within a large organization.

How Do You Become a Detective in a Specific Field?

You may be keen to pursue a particular or related field of detective work.

For example, how do you become a homicide detective or one who specializes in fraud?

As a police detective, you may have started on a path of specialization during your time as an officer.

Alternatively, moving into a detective role may be your first step into a specific field of law enforcement.

As a private detective or investigator, your specialization will generally decide the type of PI license you apply for.

This specialization may have started during your previous employment.

Detective specializations include but are not limited to:

  • Homicide – Murder investigations
  • Cybercrime – Investigating computer hacking and other online illegal activities
  • Narcotics – Drug-related crime
  • Special victims – Child and domestic abuse, sexual abuse, human trafficking and other forms of exploitation
  • Missing persons

Bear in mind when considering how to become a homicide detective, narcotics detective or any other type of specialist that moving into an area of specialization may require further training and work experience.

How Long Does It Take to Become a Detective?

You may be wondering, how many years does it take to become a detective? As a general guideline, it may take five years or longer to become a police detective.

This includes six to eight months at a police academy, several months of field training and then at least three years’ experience as a police officer before you will be considered for a detective role.

Depending on the US state and police department, you may also be expected to hold a relevant degree, which can take three or four years to complete.

How Long Does It Take to Become a Homicide Detective, a Cybercrime Detective or a Fraud Detective?

Simply put, how long to become a detective could vary greatly depending on specific US states and department requirements to obtain these and other specialized roles.

To become a licensed private detective can take up to six years, depending on the US state you want to work in and the requirements linked to the detective license you wish to obtain.

As with preparation to be a police detective, you will need to carry out training and gain relevant experience in addition to taking the relevant private investigator test.

Frequently Asked Questions

The best way to start a police detective career is to gain the required education, enroll in a police academy and work for a number of years as a police officer.

To start a private detective career, check what the requirements are in your US state and for the specific PI license you wish to obtain.

As with a police detective career path, gain the required education and experience.

It can be a lengthy process to become a detective and commitment is needed to obtain the correct training and experience.

How many years to become a detective will vary depending on different US states and department requirements, but regardless you will need to be determined to stick to your chosen path.

To become a detective, you must have relevant experience. You can, however, set out on the path to become a detective with no experience as long as you are willing to train and develop the required experience.

There are police detectives and private detectives.

Beyond that, detectives of either type may specialize in areas such as homicide, cybercrime, fraud, special victims, narcotics and commercial crime.

The answer varies depending on the US state, police department and whether you want to be a police detective or a private investigator, but is generally between 18 and 21 years old.

However, the process to become a detective can take five or six years so you are likely to be in your mid to late twenties before you become a detective.

The type of skills required to carry out detective work are a mixture of hard and soft skills that include inquisitiveness, empathy, investigation, communication skills, decision-making, resourcefulness, patience, writing skills, problem solving, critical thinking, attention to detail, emotional intelligence and situational judgement.

A criminal investigator is a type of detective. They may work for a police department or as a private detective.

An individual may also be referred to as either a criminal investigator or detective depending on the department they work in or what area they specialize in.

If you’re considering how to become a detective or criminal investigator, it’s worth knowing that the roles often share many similar responsibilities.

Working as a detective is a demanding role that requires lengthy training and several years of experience to achieve.

You will often work long and irregular hours and the role can be physically, mentally and emotionally taxing.

Detective work is often stressful because of the cases you will face and the long and irregular hours you will be asked to work.

This will depend on the police department you work in and your level of seniority.

Currently, the highest paying police departments are California, Connecticut and Maryland.

As a private detective, your pay will depend on your experience, where in the US you work, who your clients are and whether you are self-employed or work for a detective agency or larger organization.

Whether you wish to work as a police or private detective, you must be at least 18 years old (depending on the US state or police department), a US citizen, have no criminal convictions, have the relevant training and experience and be able to pass a detective test.

In most US police departments, there are three ranks of detective.

However, some begin at grade three and progress to grade one while other police departments start at grade one.

Whichever grading system is used, progression from one grade to the next brings a higher detective salary and more responsibility.

Final Thoughts

Working as a police or private detective demands a combination of training, experience and a relevant skill set.

It is a demanding but rewarding role if your heart and ambition lie in a law enforcement career.

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