Collect, identify, classify, and analyze physical evidence related to criminal investigations. Perform tests on weapons or substances, such as fiber, hair, and tissue to determine significance to investigation. May testify as expert witnesses on evidence or crime laboratory techniques. May serve as specialists in area of expertise, such as ballistics, fingerprinting, handwriting, or biochemistry.

Testify in court about investigative and analytical methods and findings. Keep records and prepare reports detailing findings, investigative methods, and laboratory techniques. Interpret laboratory findings and test results in order to identify and classify substances, materials, and other evidence collected at crime scenes. Operate and maintain laboratory equipment and apparatus. Prepare solutions, reagents, and sample formulations needed for laboratory work. Analyze and classify biological fluids using DNA typing or serological techniques. Collect evidence from crime scenes, storing it in conditions that preserve its integrity. Identify and quantify drugs and poisons found in biological fluids and tissues, in foods, and at crime scenes. Analyze handwritten and machine-produced textual evidence to decipher altered or obliterated text or to determine authorship, age, and/or source. Reconstruct crime scenes in order to determine relationships among pieces of evidence. Examine DNA samples to determine if they match other samples. Collect impressions of dust from surfaces in order to obtain and identify fingerprints. Analyze gunshot residue and bullet paths in order to determine how shootings occurred. Visit morgues, examine scenes of crimes, or contact other sources in order to obtain evidence or information to be used in investigations. Examine physical evidence such as hair, fiber, wood or soil residues in order to obtain information about its source and composition. Determine types of bullets used in shooting and if fired from a specific weapon. Examine firearms in order to determine mechanical condition and legal status, performing restoration work on damaged firearms in order to obtain information such as serial numbers. Interpret the pharmacological effects of a drug or a combination of drugs on an individual. Confer with ballistics, fingerprinting, handwriting, documents, electronics, medical, chemical, or metallurgical experts concerning evidence and its interpretation. Compare objects such as tools with impression marks in order to determine whether a specific object is responsible for a specific mark.

Law and Government -- Knowledge of laws, legal codes, court procedures, precedents, government regulations, executive orders, agency rules, and the democratic political process. Chemistry -- Knowledge of the chemical composition, structure, and properties of substances and of the chemical processes and transformations that they undergo. This includes uses of chemicals and their interactions, danger signs, production techniques, and disposal methods. English Language -- Knowledge of the structure and content of the English language including the meaning and spelling of words, rules of composition, and grammar. Customer and Personal Service -- Knowledge of principles and processes for providing customer and personal services. This includes customer needs assessment, meeting quality standards for services, and evaluation of customer satisfaction. Public Safety and Security -- Knowledge of relevant equipment, policies, procedures, and strategies to promote effective local, state, or national security operations for the protection of people, data, property, and institutions.

Science -- Using scientific rules and methods to solve problems. Speaking -- Talking to others to convey information effectively. Quality Control Analysis -- Conducting tests and inspections of products, services, or processes to evaluate quality or performance. Reading Comprehension -- Understanding written sentences and paragraphs in work related documents. Critical Thinking -- Using logic and reasoning to identify the strengths and weaknesses of alternative solutions, conclusions or approaches to problems. Active Listening -- Giving full attention to what other people are saying, taking time to understand the points being made, asking questions as appropriate, and not interrupting at inappropriate times. Writing -- Communicating effectively in writing as appropriate for the needs of the audience. Active Learning -- Understanding the implications of new information for both current and future problem-solving and decision-making. Equipment Selection -- Determining the kind of tools and equipment needed to do a job. Coordination -- Adjusting actions in relation to others' actions.

Inductive Reasoning -- The ability to combine pieces of information to form general rules or conclusions (includes finding a relationship among seemingly unrelated events). Near Vision -- The ability to see details at close range (within a few feet of the observer). Oral Expression -- The ability to communicate information and ideas in speaking so others will understand. Speech Clarity -- The ability to speak clearly so others can understand you. Oral Comprehension -- The ability to listen to and understand information and ideas presented through spoken words and sentences. Information Ordering -- The ability to arrange things or actions in a certain order or pattern according to a specific rule or set of rules (e.g., patterns of numbers, letters, words, pictures, mathematical operations). Deductive Reasoning -- The ability to apply general rules to specific problems to produce answers that make sense. Written Expression -- The ability to communicate information and ideas in writing so others will understand. Problem Sensitivity -- The ability to tell when something is wrong or is likely to go wrong. It does not involve solving the problem, only recognizing there is a problem. Speech Recognition -- The ability to identify and understand the speech of another person.

Inductive Reasoning -- The ability to combine pieces of information to form general rules or conclusions (includes finding a relationship among seemingly unrelated events). Near Vision -- The ability to see details at close range (within a few feet of the observer). Oral Expression -- The ability to communicate information and ideas in speaking so others will understand. Speech Clarity -- The ability to speak clearly so others can understand you. Oral Comprehension -- The ability to listen to and understand information and ideas presented through spoken words and sentences. Information Ordering -- The ability to arrange things or actions in a certain order or pattern according to a specific rule or set of rules (e.g., patterns of numbers, letters, words, pictures, mathematical operations). Deductive Reasoning -- The ability to apply general rules to specific problems to produce answers that make sense. Written Expression -- The ability to communicate information and ideas in writing so others will understand. Problem Sensitivity -- The ability to tell when something is wrong or is likely to go wrong. It does not involve solving the problem, only recognizing there is a problem. Speech Recognition -- The ability to identify and understand the speech of another person.