Crime Scene Investigator

(job description)


This position is responsible for complex crime scene investigations; responsibility for the evaluation of the scene; uses various types of equipment; develops, secures, and packages physical evidence for scientific evaluation and comparison; prepares detailed reports on the observations and activities at the scene for the law enforcement agency responsible for the investigation of  the crime; testifies in court regarding the findings and processing methods used at the scene.


Working Conditions: The crime scene investigator oversees complex crime scene investigations, including but not limited to homicides, sexual assaults, armed robberies, home invasions, and property crimes such as burglaries. Approximately 70% of the incumbent's time is spent processing crime scenes, packaging and transporting evidence, attending and photographing autopsies and attending briefings and conferences with the police agencies requesting assistance. The remaining time is spent preparing investigative reports, testifying in court, receiving continuing education, via online education or in class course work, instructing classes and maintaining equipment in a state of readiness.

The crime scene investigator works at the office of his or her job assignment Monday through Friday, which is normally 8:30 a.m. to 4:30 p.m. Must accept scheduled after-hours standby duty every other week. While on standby, the crime scene investigator must be readily available by pager or phone at all times to respond to requests for service. In addition to the standby duty, the incumbent is expected to respond to emergency calls whenever necessary 24 hours a day.

Crime scene searches are often performed by extensive kneeling, stooping, reaching and climbing. The crime scene investigator will handle objects of varying weight and shape and must, therefore, be in good physical condition. The incumbent is also required to carry firearms and may use assigned firearms and other weapons in performance of his or her police enforcement responsibilities. Also, the police enforcement responsibilities may include occasional physical labor and endurance and be hazardous with regard to the physical and mental well being of the incumbent.

Functions: The crime scene investigator is expected to respond to calls for crime scene services as quickly as good judgment and safety allows. All issued equipment must be maintained in a ready-to-use condition at all times.

Process scenes of major crimes at any hour of the day or night, under any weather conditions, systematically surveys area and formulates a plan of procedure. Physically secures crime scenes (using ropes, barricades, police personnel, etc.) before conducting a search for all objects and articles that may be evidence. The crime scene investigator must also be proficient in "reading" and reconstructing the events as they happened just prior to, during and shortly following the commission of the crime in order to determine the sequence of events and to ascertain the type and location of evidence. Gives advice and direction to case investigators in crime scene and evidentiary matters.

Evidence identified must be collected and properly packaged. This function includes efficient lifting and preserving of various types of evidence. The crime scene investigator must be aware of the types of packaging and packaging material as the improper selection of such material could render the evidence useless.

The crime scene investigator establishes a permanent record describing the crime scene by writing detailed reports, preparing accurate sketches, and diagrams and by applying professional photographic techniques. This requires not only the skill to write a detailed report but also the ability to observe minute details of the scene as they relate to the crime and their meaning in relation to the evidence.

The incumbent assists criminal justice officials in preparing criminal cases, in person and by providing reports, sketches, and photographs. Gives expert testimony in criminal court cases. This testimony must not only follow the rules of evidence but must also be able to explain, in laymen's terms, to a jury the significance of the evidence as it relates to scientific proof. Maintains an in-depth knowledge of federal and state statutes, court cases related to work performed and agency rules and regulations.

The incumbent must prepare and forward all necessary administrative reports and forms in keeping with division and bureau policies.

Latitude: The crime scene investigator has authority to determine the extent and nature of the services needed at the crime scene. This includes what technical procedures to follow and what specialized equipment, lighting, auxiliary power, etc. to use.

Major Challenge: The greatest challenge of this position is to apply scientific expertise in crime scene evidence identification and processing with the ultimate goal of successful prosecution of the offender in a court of law.

Contacts: The incumbent must frequently interact, on a professional basis, with law enforcement officials at all levels, state and federal prosecutors, county coroners, medical examiners and pathologists in person or by telephone.

Knowledge and Experience: The crime scene investigator must successfully complete a minimum of 720 hours training in crime scene processing with a minimum of 80 hours training in latent fingerprint processing, 40 hours in major death investigation, 40 hours in advanced death investigations, 40 hours in photography, 40 hours in blood spatter interpretation and other training courses in arson investigation and forensic pathology. In addition, the crime scene investigator must be certified by the International Association for Identification, Crime Scene Certification Board, within 18 months as a crime scene investigator.

Selection as a crime scene investigator must be based upon a demonstrated knowledge of police investigative techniques, search and seizure and the police officer's role in criminal prosecution. The incumbent must have or acquire an in-depth knowledge of department and division policies and practices relating to his or her position, Illinois criminal law and procedure and pertinent case law. Skills must be acquired in the fields of science, chemistry, anatomy and the forensics, in addition to those needed for actual crime scene processing. Power of arrest and the authority to carry a weapon and possession of a valid driver license in the appropriate classification required by law are also required.

Thorough knowledge in the proper chemicals used for evidence development based on the type of materials being processed and employed for a particular situation is needed. The incumbent must be aware of the proper procedures for crime scene sketching. A proper understanding of photographic lighting, distortion and proper lens and camera selection is necessary for properly recording a scene photographically.

Abilities: Requires ability to qualify with firearms as required by department policy. Requires ability to conform with the department's physical fitness and defensive tactics standards. Requires ability to operate and maintain assigned police vehicle and equipment. Requires a clear speaking voice, the ability to receive, understand and act upon oral instructions thorough the use of a radio. Requires ability to lift heavy objects and equipment weighing up to 100 pounds. Requires ability to walk, stand, stoop, crawl, kneel, climb and push/pull objects. Must be able to visually identify or describe persons, vehicles, locations or describe physical evidence and crime scenes by sketching, report writing and providing courtroom testimony. Be able to effectively and accurately document enforcement and investigative activities in handwritten reports.


1.    Assumes a high degree of accountability for delivering the highest quality crime scene investigative service possible. This accountability attaches not only to the actual processing of the crime scene, but includes all follow-up tasks.

2.    Prepares necessary investigative reports and documentation for court cases. Appears and testifies in official proceedings.

3.    Maintains in a state of readiness all technical equipment and assigned vehicles.

4.    Performs other duties as assigned or required.