Criminalists analyze, identify, and draw conclusions derived from physical evidence. A criminalist’s most important duty is to use their skills and experience to objectively examine physical evidence. They identify important evidence and discard evidence with no value. They base these valuations using scientific methods and then identify, sort, and match similar pieces of evidence that could be used in a trial. Making interpretations from the evidence, and performing tests on it, is one of the criminalists’ most important duties because events that occurred at a crime scene can be identified and witnesses’ testimonies can be validated. Criminalists also prepare reports and provide expert testimony.
What do Criminalists do?
Criminalistics is the forensic science of interpreting and analyzing evidence using an advanced understanding of natural sciences as well as scientific techniques. Forensic science, in particular, pertains to all sciences that are used to solve and address legal problems and issues. As the name denotes, criminalists use the science of criminalistics to solve crimes. They identify and examine evidence to first understand and then reconstruct a crime scene. Physical evidence can be a piece of clothing, a weapon, drugs, a bloodstain, or even a residue vapor in the air. Criminalists use this physical evidence to establish a link between a victim and the suspected perpetrator of the crime. The transfer of fibers from clothing or strands of hair between a victim and the suspect can establish just such a link. Bullet fragments, fingerprints, and shoe prints are other important links that criminalists look for when trying to reconstruct the crime scene.
Evidence collected from a crime scene may include the victim’s body or any other items related to the crime. Criminalists themselves often collect physical evidence at crime scenes but they also receive and analyze evidence provided to them by crime scene investigators. Employing the correct methodology for the collection of evidence is imperatives in order to prevent contamination, degradation or destruction of the physical evidence. After evidence has been collected it is taken to the crime lab. At the crime lab, Criminalists perform a variety of tests depending on the type of evidence present. Criminalists are frequently required to visit court to offer expert testimony regarding their findings and their method of analysis.
Criminalists’ typical tasks include the following:
- Examine, test, and analyze chemical substances, tissue samples, physical materials, and ballistics evidence, using modern measuring, testing, and recording equipment.
- Interpret and evaluate laboratory findings and test results to identify and then classify materials, substances, and other crime scene evidence.
- Collect, record, and preserves criminal evidence required to solve the case.
- Confer with fingerprinting, ballistics, handwriting, documents, medical, electronics, chemical, and/or metallurgical experts with regard to crime scene evidence and its interpretation.
- Reconstruct crime scene in order to determine the relationship between each piece of physical evidence.
- Prepare reports or presentations of test results, finds, conclusions, laboratory techniques, or investigative methods.
- Testify as expert witness laboratory techniques or evidence presented in hearings or trials.
The following are common procedures and analysis regularly performed by criminalists:
DNA typing is conducted when a sample of body fluid such as saliva, blood, or semen is collected from the crime scene. DNA typing is a process that provides a Criminalist with a type of genetic blueprint that helps to identify a unique individual. Criminalists try and use the results of DNA typing to identify a suspect — and sometime even a victim. Proper handling and storage of crime scene evidence is essential in order to preserve DNA test samples.
Drug identification is a investigative process employed by Criminalists to identify and analyze illegal substances such as heroin, cocaine, and marijuana, which are typically found in vials or plastic bags at crime scenes. Criminalists have to interpret the results of drug testing and analyses to determine their significance to the case at hand.
Firearms and toolmarks analysis requires the examination and analysis of any firearm that is believed to have been used to perpetrate a crime. Criminalists use forensic analysis to determine the type of bullet used and if the bullet fired from the gun was the same bullet used to commit the crime. Toolmark analysis involve the analysis any object that is suspected of containing the impression of any other object that was used as a tool to commit a crime. For example, a wrench makes a unique and identifiable impression when scraped along a wall, floor or other surface. A Criminalist is required to analyze the marks that the wrench — or any other tool for that matter — left behind.
Impression evidence is the evaluation and analysis of impressions made by tires, shoes, depressions in soft soils, and all other forms of impressions and tracks left at the crime scene. These also include glove and other fabric impressions, as well as bite marks in food and unfortunately skin. Criminalists may also analyze impressions left on dusty surfaces to reveal hidden fingerprints.
Serology is a very common procedure performed by Criminalists. Serology is the evaluation and analysis of body fluid evidence that includes semen stains, bloodstains, and saliva. Criminalists use serology to determine both the identity and origin of a substance. Criminalists analyze dried blood dried left in fabrics or other objects, as well as cigarette butts that may contain saliva from a criminal. Often serology will reveal evidence that is not visible to the human eye. Blood obviously is quite visible due to its reddish color, however an artificial forensic light source is often required in order to find other body fluid evidence such as semen. All evidence containing stains from the crime scene must stay dry and be stored at a cool temperature to ensure its integrity.
Trace evidence is one of the more common procedures Criminalists use to reconstruct a crime scene and identify a criminal. Trace evidence is the evaluation and analysis of fibers, hairs, paint chips, wood, glass, and soil that are found at a crime scene. Analysis of trace evidence assist Criminalists to identify a relationship between a victim and the suspect. A hair may be taken from the victim’s body establishing a strong relationship between a potential suspect and the victim. A fiber found on a deceased or assaulted victim may reveal a fiber from carpet unique to the car being driven by the suspect. Once trace evidence has been discovered, a Criminalist or other criminal scene technician or investigator collects the evidence from the crime scene using a special pari of tweezers and promptly places the evidence in a folded paper cone, which in turn is placed into a sealed envelope used for storing and transporting evidence from the crime scene to the laboratory. Trace evidence scrutinized and analyzed to determine its origin and composition once it arrives at the laboratory.
Skills required to be a top Criminalist
The following are important skills, knowledge, and abilities successful Criminalists require in order to perform their jobs.
- Information Gathering – This entails having the ability to gather information and then identify essential information.
- Information Organization – Ability to classify or structure multiple pieces or groups of information.
- Information Ordering – Ability to correctly apply a rule or set of rules in order to arrange items or actions in a useful order. The things or actions may include letters, numbers, words, procedures, pictures, sentences, and logical or mathematical operations.
- Problem Identification – Identifying the type, nature and significance of problems.
- Reading Comprehension – Comprehending written sentences and paragraphs in work related documentation.
- Critical Thinking – Employing logic and analysis to identify and evaluate the strengths and weaknesses of different analytical approaches.
- Chemistry – Knowledge of the structure, composition, and physical properties of substances and of the chemical processes that they undergo. This often includes uses of particular chemicals as well as their interactions, production techniques, danger signs, and disposal methods.
- Science – Applying scientific methods to solve problems.
- Public Safety and Security – Knowledge of public safety, weaponry, and security rules, operations, regulations, prevention, precautions, and the protection of data, people, and property.
- Inductive Reasoning – The ability to combine and evaluate separate pieces of related information, or answers to problems, to develop general rules or conclusions. It includes developing a logical explanation as to why series of what appear to be unrelated events occur together in combination with one another.
- English Language – In-depth knowledge of the structure, content, and meaning of the English language including both the spelling and meaning of English words, grammar, and rules composition.
- Oral Expression – The ability to verbally communicate ideas, concepts, and information in a manner that others understand.
Criminalists work in a crime laboratory and at crime scenes. The lab is well lighted, ventilated, and clean. Criminalists have office space that includes a desk and computer. Since Criminalists are in contact with physical evidence, they are exposed to disease, chemicals, odors, and fumes. Therefore, Criminalists must wear protective and disposable clothing such as gloves, eyewear, paper suits, and paper shoe coverings when handling body fluid evidence to prevent the transmission of disease. Criminalists are often called to court to provide expert testimony regarding their methods and findings.
Where do criminalists work?
Criminalists work at sheriffs’ offices, forensic laboratories, state and regional agencies, universities, medical examiners’ offices, federal agencies, and private companies.
Criminalist Training and Education
Potential criminalists must earn a bachelor’s degree in one of the physical, biological, or forensic sciences in conjunction with at least 24 credit hours of chemistry, biology, or math. Classes taken are often more important than the actual degree. Criminalists must also participate in continuing education throughout their careers.Licensing and certification requirements
No current mandated requirements exist for criminalists, but most criminalists become certified by the American Board of Criminalistics. The American Society of Crime Laboratory Directors or the Laboratory Accreditation Board may provide accreditation to entire forensic labs.
According to the Bureau of Labor Statistics, criminalists can earn between $33,880-95,600 annually. Federal criminalists usually earn even higher pay.
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