By Leslie Doyle | 07/03/2025
What is a criminalist? When a crime occurs, it is a criminalist’s job to help solve a mystery. Criminalists apply scientific principles to real-world investigations, working closely with law enforcement to uncover the truth behind crimes.
Criminalists go to crime scenes to analyze evidence. They commonly work alongside a crime scene investigator who identifies and collects forensic evidence. Evidence gathered by crime scene investigators may include items such as:
- Fingerprints and footprints
- Fibers from clothing or other materials
- Biological material such as blood, hair, or other tissues
- Weapons, such as firearms
- Tire tracks
- Controlled substances
- Tool marks
The Criminalist’s Role in an Investigation
A criminalist’s role involves applying scientific methods to assess trace and physical evidence to aid criminal investigators understanding the circumstances of the crime. Ideally, they reconstruct crimes and match evidence to specific perpetrators.
Criminalists often play a central role in law enforcement cases. As forensic science experts, criminalists are called on by law enforcement agencies to serve as expert witnesses in court to help prosecutors build their cases. Their work is pivotal in law enforcement investigations and the pursuit of justice.
The Impact of a Criminalist
Jennifer Bucholtz is an instructor of forensic sciences and criminal justice at American Public University (APU). She also serves as a cold case investigator for the El Paso County Sheriff’s Office.
“Last year, my agency got a call for service from someone who was the victim of a road rage incident,” says Bucholtz. “The offender had fired a bullet through a car door, narrowly missing the leg of the victim.”
“Detectives from our investigations unit were called out, as was a criminalist with specialized training in ballistics and trajectory analysis. They recovered a bullet from inside the vehicle and determined a likely suspect based on information from the victim and nearby camera footage.
“Ultimately, the criminalist was able to link the bullet to a weapon owned by that suspect. That, coupled with the other evidence, was enough for the detective to obtain an arrest warrant. The suspect was arrested and later convicted of several felonies.”
Working as a Criminalist
Criminalists are vital in the criminal investigations cycle and in helping victims and families to obtain justice. Their work helps investigators develop new leads that may lead to an arrest or provide answers about a crime.
“Having this type of involvement in seeking justice can be very rewarding and satisfying,” says Bucholtz. “However, the type of scenes that some criminalists process as a routine part of their job can lead to secondary trauma and PTSD.
“Most humans never witness the disturbing acts associated with homicides, serious car accidents, domestic violence, or sexual assault on children. Criminalists may have to be involved in the processing of these types of crimes as well as communication with victims. This work can be very difficult to handle mentally, and self-awareness is essential.
“Being a criminalist also involves tedious and repetitious steps, particularly when you’re processing a crime scene for physical evidence or analyzing physical evidence in the forensic lab. The job requires you to be detail-oriented and patient.”
Where Do Criminalists Work?
Career opportunities in criminalistics are varied. For a criminalist, they generally include working in settings such as:
- Crime scenes
- Crime labs
- Courtrooms
Crime Scenes
A criminalist may use various tools to identify materials that may be relevant to the investigation. Depending on the specific crime, they may:
- Assess and document a crime scene
- Collect, preserve, and transport evidence
- Extract DNA for analysis
- Conduct bloodstain pattern analysis
- Create casts to analyze impressions
Crime Labs
Laboratory analysis is a crucial element of the job for criminalists or forensic science technicians. Criminalists collaborate with police officers and other professionals in law enforcement agencies who are tasked with investigating specific crimes.
As part of their work, criminalists often perform DNA sequencing. This powerful scientific analysis makes it possible to identify a suspect or victim based on DNA in blood, tissue, hair, or other human material found at a crime scene.
Criminalists may be able to match evidence found at the scene to a perpetrator by comparing it against relevant databases (for example, the Automated Fingerprint Identification System or AFIS). A criminalist may also perform tool mark analysis to help identify a weapon used in a crime.
Courtrooms
Criminalists are often called upon to present their expert testimony in a courtroom to support criminal charges against a suspected perpetrator. They share their objective analysis from a written report or present it orally during a trial.
As an expert witness in court, criminalists need to explain their scientific analysis in simple terms so that everyone present – including the judge, attorneys, and jury – can understand the information they share.
Potential Career Paths for Criminalists
Criminalistics professionals – who can also be known as forensic scientists – often work for local, state, or federal agencies responsible for law enforcement. The Federal Bureau of Investigation (FBI), the Drug Enforcement Administration (DEA), and the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) are some of the government agencies that are known to hire this type of professional.
Additional career opportunities exist in police departments, crime labs, private companies, and universities.
The Skills Every Criminalist Needs
Criminalists use their expertise in forensic science (such as molecular biology, forensic biology, chemical analysis, and natural sciences) to study crime scene evidence. The information they uncover may help identify or rule out a suspect, establish the time a crime occurred, or piece together what transpired during a crime.
Aspiring criminalists will need a combination of education, hands-on experience, and certifications. Additionally, there are many skills that criminalists should develop to thrive in this field:
- Analytical skills
- The ability to remain calm under pressure
- Communication skills
- Attention to detail
- Integrity
- Objectivity
- Stress management
- Problem-solving skills
Criminalists must create detailed written reports that become part of a case file. Consequently, professional writing skills are also critical to this role. Potential candidates should not only have the required knowledge and skills but will also need to pass a background check.
Why Meticulous Crime Scene Work Matters
Being a criminalist requires being meticulous in your work, whether you’re collecting evidence or interacting with the crime lab. “Rushing through a crime scene can lead to overlooking critical evidence, which could harm a case or cause it to go unsolved,” says Bucholtz.
“Not following proper protocol with regards to wearing – and frequently changing – protective equipment can lead to contamination of a crime scene or pieces of evidence. Contamination or mishandling can lead a judge to rule certain evidence as inadmissible in a court of law.”
Criminalists may also be tasked with photographing a crime scene, including taking overall (wide-range photos that include large parts of a crime scene), midrange, and up-close photos. They may have to sketch the scene and take many measurements.
“A failure to properly document the scene with these tactics may negatively affect the success of the investigation and present problems for a prosecutor explaining the crime scene to jurors during a trial. It can also make it difficult to re-create the scene later if a re-creation is needed,” Bucholtz explains.
Criminalists must create detailed written reports that become part of a case file. Consequently, professional writing skills are also critical to this role.
What Education Is Needed to Become a Criminalist?
A bachelor's degree in biology, chemistry, criminal justice, or forensic science is typically required for entry-level positions. Some roles in this field require more advanced degrees, such as a master's degree.
Professional Certifications
Professional certification is also useful for criminalists. The American Board of Criminalistics offers certifications in various subjects, including:
- Biological evidence screening
- Comprehensive criminalistics
- Drug analysis
- Forensic DNA
- Foundational knowledge
According to the Board’s website, the exams are designed for practicing forensic scientists. Although some test questions are related to subjects a student learns while earning a degree in forensic science, others are intended to assess the competency of someone with hands-on experience.
Other Types of Education
Hands-on experience may also be needed to gain the foundational knowledge to work as a criminalist. To gain on-the-job training, some students pursue internships.
Many agencies across the country now offer internships, some of which are paid. These opportunities provide a chance to gain practical experience in a set amount of time.
Criminalist Specializations
Criminalists may choose to specialize in a specific forensic science discipline, such as firearms, toxicology, or DNA analysis. Criminalists can also specialize in trace evidence by gaining in-depth knowledge of chromatographic, microscopic, and spectroscopic analytical techniques. This type of specialization allows for the analysis of microscopic evidence found at a crime scene.
“The field of criminalistics is actually very wide,” says Bucholtz. “It has many sub-disciplines that are more focused than that of traditional crime scene investigation.”
Additional specialty career paths include:
- Chemical analysis
- Arson analysis
- Wildlife forensic science
- Toolmark identification
Considering a Career Path as a Criminalist in the Criminal Justice System?
“If you’re thinking about a career as a criminalist, I recommend seeking out internships or volunteer opportunities first to see if the job is a good fit for you,” says Bucholtz. “People may think they are mentally prepared for such a job, but many may find that being a criminalist is too tedious and overwhelming.”
“I'd also suggest taking some college or seminar courses on crime scene investigation, digital photography, DNA analysis, blood spatter analysis, and evidence collection,” Bucholtz advises. "Classes in chemistry are often required for criminalist jobs. Most bachelor’s degree programs in forensic science include these types of courses.”
The Bachelor of Science in Criminal Justice at APU
Adult learners who are interested in studying forensic science, criminal behavior, digital forensics, and other crime-related topics may opt to pursue APU’s online Bachelor of Science in Criminal Justice. This degree features a concentration in digital forensics to enable students to develop their knowledge of cybercrime and digital forensics investigations.
Courses in this academic program involve topics such as criminology, criminal profiling, and criminal investigation. Other courses include criminalistics, criminal law, crime analysis, and criminal justice administration.
For more information about this degree, visit APU’s security and global studies program page.
Note: This degree program is not designed to meet the educational requirements for professional licensure or certification in any country, state, province, or other jurisdiction. This program has not been approved by any state professional licensing body and does not lead to any state-issued professional licensure.
