Criminalists examine and identify physical evidence and derive conclusions from it. Their most important responsibility is to utilize their knowledge and training to objectively analyze evidence. Criminalists identify significant evidence and remove valueless evidence. They utilize scientific procedures when determining the value of evidence before identifying, classifying, and comparing similar evidence that can be used by police investigators and prosecuting attorneys. Drawing conclusions from, and testing evidence is one of the most important responsibilities of a criminalist since events taking place during a crime can be confirmed and witness reports validated. Additionally, criminalists write reports containing their expert opinions and testify at court.

What do criminalists do?
Criminalists are forensic science specialists who utilize scientific procedures and advanced scientific knowledge to evaluate and interpret physical evidence. Forensic science is a scientific field pertaining to investigative methods used to solve crimes. Criminalists evaluate physical evidence to determine its value and make educated assumptions about transpired events at crime scenes. Physical evidence includes weapons, clothing, human blood and tissue, drugs, and any object providing answers about a crime. Criminalists analyze this evidence to develop a connection between victims and suspected criminals. The transfer of hair strands or clothing fibers from the criminal to victim or vice versa can establish a connection. Criminalists also look for shoe prints, fingerprints, bullet fragments, and other pieces of evidence that link suspected criminals to crimes.

Criminalists frequently collect evidence from crime scenes, and they evaluate evidence transferred to them from other investigators. Criminalists must utilize correct procedures when collecting evidence to avoid destroying or contaminating it. Once evidence is retrieved, it's transferred to crime laboratories where criminalists perform numerous tests to analyze it and determine its relevance. They also frequently provide expert testimony at court detailing their conclusions.

Criminalist typical tasks include the following:

  • Inspect, test, and evaluate chemicals, ballistics, hair strands, tissue and body fluid samples, and other pieces of physical evidence by utilizing modern technology and scientific procedures
  • Interpret and analyze laboratory test results to determine and categorize chemicals, materials, and other pieces of physical evidence
  • Process and record physical evidence that will be used to solve crimes
  • Collaborate with handwriting, fingerprinting, medical, ballistics, chemical, and metallurgical specialists to analyze evidence collected from crime scenes
  • Reconstruct the assumed events occurring during a crime to determine where physical evidence fits in
  • Write reports and prepare presentations detailing conclusions and techniques used to reach them
  • Provide expert testimony at trials and hearings

The following are typical procedures used by criminalists to develop conclusions:

DNA typing - when blood, tissues, semen, or other bodily fluids are collected at crime scenes, criminalists use DNA typing, a process used to create a genetic blueprint that is unique to a specific person. After DNA typing is conducted, criminalists can take the DNA blueprint and compare it to DNA samples collected from victims and suspected criminals. It's essential that DNA evidence collected at crime scenes is retrieved, transferred, and stored properly to prevent contamination.

Drug identification - is an investigative method used by criminalists to detect and analyze drugs, including marijuana, pharmaceuticals, marijuana, cocaine, and other controlled substances found at crime scenes. Criminalists must evaluate drug tests to ascertain whether results are relevant to a criminal investigation.

Firearms and toolmarks analysis - is a test used to analyze guns which are suspected to have been utilized during a crime. Criminalists conduct forensic analysis to identify bullets and casing and match them to specific guns. Toolmark analysis is used to determine whether an object found at a crime scene carries an impression from a tool used during a crime. For example, wrenches leave distinctive impressions when scrapped against a floor or wall. Criminalists are responsible for examining the impression left by a wrench or other tools create.

Impression evidence - criminalists analyze impressions created by shoes, tires, and other objects that leave distinctive tracks or impressions. Also included are bite marks, puncture impressions, and fabric and glove impressions. Additionally, they examine impressions found on dusty surfaces to locate fingerprints and other pieces of physical evidence.

Serology - is a method frequently utilized by criminalists involving the examination and analysis of blood, saliva, semen, and other body fluids. Criminalists rely on serology to identify where a retrieved fluid originated from. They analyze blood stains found on cloths and surfaces, in addition to cigarette butts containing traces of saliva. Frequently, serology results reveal microscopic blood and fluids. Criminalists frequently use forensic lights to locate bodily fluids which are not colorful or visible like semen. Bodily fluids retrieved from crime scenes must be handled and stored properly at appropriate temperatures.

Trace evidence - is a frequently utilized method criminalists utilize to reenact crimes and identify potential suspects. Trace evidence includes fibers, paint chips, hair strands, glass, wood, soil, and other pieces of physical evidence retrieved at crime scenes. Examining trace evidence often enables criminalists to identify links between suspected criminals and victims. For example, hair fibers recovered from victim's clothing can be used to identify suspects. Fibers retrieved from corpses or injured victims can be traced back to a specific type of car. After trace evidence is identified, criminalists or other investigators retrieve it with specialized tweezers or other tools and place it in a sealed folder which is eventually transported to crime laboratories. Evidence is then thoroughly examined and analyzed to determine composition and origin.

Skills required to be a top criminalist
Successful criminalists typically possess the following essential knowledge and skills:

  • Information Gathering - Criminalists must be able to gather essential information and recognize vital information
  • Information Organization - Ability to organize and categorize numerous quantities of information
  • Information Ordering - Ability to properly utilize rules to categorize items or methods in an effective order, including letters, scientific methods, sentences, pictures, and mathematical and logical methods
  • Problem Identification - Determining the type, significance, and nature of problems
  • Reading Comprehension - Understanding written content read during work procedures
  • Critical Thinking - Utilizing analytical methods and logic to determine and analyze weaknesses and strengths of various scientific methods
  • Chemistry - Basic understanding of the physical composition, structure, and reactions of various chemicals. Criminalists must also understand how various chemicals are manufactured and disposed and harm human health
  • Science - Utilizing scientific procedures to resolve problems
  • Public Safety and Security - Understanding of public safety, security, weaponry, and other important laws and regulations intended to protect people, property, and data
  • Inductive Reasoning - Ability to link multiple pieces of similar evidence to solve problems and develop conclusions. Criminalists must also be able to develop rational explanations for why series of unrelated occurrences are related
  • English Language - Extensive knowledge of English vocabulary, grammar, spelling, and writing conventions
  • Oral Expression - Excellent communication skills and the ability to explain complex ideas in comprehendible language

Work Environment
Criminalists conduct investigations at crime scenes and laboratories. Criminal laboratories are sterile, ventilated, and brightly-lit. They complete a lot of work at computers in individual offices. Because criminalists handle physical evidence, they must take precautions against noxious fumes, odors, chemicals, and blood-borne disease by wearing paper shoe coverings, protective suits, goggles, and gloves. Criminalists frequently get called before juries to offer expert testimony about their conclusions.

Where Criminalists Work
Criminalists are employed at sheriffs' departments, crime laboratories, government agencies, medical examiners' offices, colleges and universities, private companies, and law enforcement agencies.

Training and Education
Aspiring criminalists need to obtain a bachelor's degree in a biological, physical, or forensic science and complete 24 credit hours in math, biology, or chemistry at a minimum. Completed courses often matter more than majors. Additionally, criminalists are required to complete periodic continuing education during their professional lives.

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Licensing and Certification Requirements
There are no pre-qualifications to begin a career as a criminalist, but most criminalists certify with the American Board of Criminalistics. The Laboratory Accreditation Board and the American Society of Crime Laboratory Directors are two organizations that accredit crime laboratories.

The Bureau of Labor Statistics has reported that criminalists typically earn salaries ranging anywhere from $45,000 to 65,000 a year. Criminalists employed by the federal government typically earn higher annual salaries.

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