Duty Description for the Crime Scene Investigator
Duty Description for the
Crime Scene Investigator
by Mike Byrd
Miami-Dade Police Department
Crime Scene Investigations
The Crime Scene Investigations Bureau
The Bureau provides support services in the form of crime scene processing, fingerprint identification, and forensic imaging to department entities and other agencies. The goals and objectives of the Crime Scene Investigations units are the collection, preservation, packaging, transportation, and documentation of physical evidence left at the crime scene.
Introduction to Crime Scene Response
Most police investigations begin at the scene of a crime. The scene is simply defined as the actual site or location in which the incident took place. It is important that the first officer on the crime scene properly protect the evidence. The entire investigation hinges on that first person being able to properly identify, isolate, and secure the scene. The scene should be secured by establishing a restricted perimeter. This is done by using some type of rope or barrier. The purpose of securing the scene is to restrict access and prevent evidence destruction.
Once the scene is secured, the restrictions should include all nonessential personnel. An investigation may involve a primary scene as well as several secondary scenes at other locations. On major scenes a safe space or comfort area should be designated at the crime scene to brief investigators, store needed equipment, or as a break area.
In critical incident management the protocol that is being taught today identifies a three layer or tier perimeter. The outer perimeter is established as a border larger than the actual scene, to keep unlookers and nonessential personal safe and away from the scene, an inner perimeter allowing for a command post and comfort area just outside of the scene, and the core or scene itself. An extreme advantage will be seen by taking the time to properly teach the uniform officers and first responders to evaluate and secure the scene.
Physical Evidence at a Crime Scene
Evidence used to resolve an issue can be split into 2 areas. Testimonial evidence and physical evidence. The testimonial evidence would be any witnessed accounts of an incident. The physical evidence would refer to any material items that would be present on the crime scene. These items would be presented in an issue or incident to prove or disprove the facts of the issue. What will evidence collected at a scene do for the investigation :
- May prove that a crime has been committed.
- Establish any key elements of a crime.
- Link a suspect with a scene or a victim.
- Establish the identity of a victim or suspect.
- Corroborate verbal witness testimony.
- Exonerate the innocent.
The evidence that is located and recovered at a scene will give the detectives responsible for the investigation leads to work with in the case.
Types of Evidence
- Impressions include fingerprints, tool marks, footwear, fabric impressions, tire marks and bite marks.
- Forensic Biology includes blood, semen, body fluids, hair, nail scrapings, blood stain patterns,
- Trace Evidence includes gun shot residues, arson accelerant, paint, glass and fibers.
- Firearms includes weapons, gun powder patterns, casings, projectiles, fragments, pellets, wadding and cartridges.
- Question Documents
The Crime Scene Investigator or Evidence Recovery Technician
In the Scientific community the crime scene investigator or evidence recovery technician is accepted as a forensic specialist. His/ Her specialty is considered a professional organized step by step approach to the processing of a crime scene. Extensive study, training, and experience in crime scene investigations is needed for the investigator to be proficient in the field. He/she must be well versed in all areas of recognition, documentation and recovery of physical evidence that may be deposited at the scene. A general knowledge of what analysis may be performed in the lab as well as proper procedures in handling, collecting and packaging of items of evidence is needed to assure those recovered items will safely arrive at the lab.
The duties, assignments, and procedures vary from departments and agencies regarding the investigators or technicians. Therefore the job description may vary depending on geographic locations. For example, if you reside in an area with a large population where it consistently ranks in the top 10 nationally in violent crime occurrences, then the evidence documentation and collection portion of a crime scene response can be a full time job. Where as a geographic location with a much smaller population and fewer criminal acts might necessitate a combination of required job skills. There is also the departmentals sworn verses non-sworn personnel preferences.
Most departments today prefer, if not require some type of college degree. It would be advisable to contact the departments or agencies where you reside or will be residing to find out their particular requirements and duties.
Regardless of whether your major education is in general studies, criminal justice or forensics, a suggestion is to augment those studies with minor courses in basic computer training, drafting, and photography. Any curriculum designed for crime scene in criminal justice classes at most colleges will be developed in general studies not in specifics.
After being selected for employment most departments will have a probationary period where the employee will go through a training period (OJT= on the job training) assigned to a field training officer. Most of the experience to do the job will be gained in this phase of employment. Most departments also offer their employees an opportunity for post employment or in service training to further the employees development. Most of the post employee educational classes for the crime scene investigator would be specific classes geared to crime scene response, evidence collection, forensic photography, fingerprint technology, homicide and death scene investigation.
If the student wishes to search, There are a few colleges today that are offering programs for post graduation classes in various forensic disciplines and crime scene response.
If someone were interested in seeking a job in evidence recovery, it would help to spend a weekend at an auto body shop gaining the experience of removing a door panel, the seat, carpet, head liner or a light assembly. Many times the investigator will have to remove a door or a section of wall from a structure. Grid, dig, or sift for hours through a burial site.
Another area to gain experience is visiting the morgue or a local trauma center. This is not a custom tailored job to suit everyone. What man can sometimes do to mankind is not always a pretty sight to see. If you can not stomach a busy weekend night in the local trauma center or morgue then you will surely not stomach some of the mutilation or uncommon sights that can be common to the job.
Processing the Crime Scene
In an Organized approach to Crime Scene Investigations there are three (3) basic and simple stages in properly processing the crime scene . Those stages consist of Scene Recognition, Scene Documentation and Evidence Collection. An organized approach is a sequence of established and excepted duties and protocols.
An organized approach assures:
- a thorough and legal search is conducted.
- expeditious processing without compromise.
- proper scene documentation.
- proper methods and techniques for evidence recovery.
- proper use and knowledge of resources and equipment.
- all pertinent evidence recovery.
- proper handling and packaging of evidence.
- proper distribution points for evidence analysis.
- proper safety precautions are followed.
The recognition or discovery of evidence begins with the initial search of the scene. The search can be defined as the organized and legal examination of the crime scene to locate items of evidence to the crime under investigation. There are several search methods or patterns applied in an organized search. Factors such as the number of searchers, the size of the area to be searched, the terrain, etc. are used to determine the method or pattern to be employed in the crime scene search.
Since most investigations start with very limited information, care and common sense are necessary to minimize the chances of destroying evidence. A plan of operation is developed and initiated from an initial walk through of the scene. The plan is to decide what evidence may be present, what evidence may be fragile and need to be collected as soon as possible. What resources, equipment, and assistance are necessary for the processing. Consideration of hazards or safety conditions may need to be addressed.
In the documentation stage of an organized approach for processing the crime scene all functions have to correspond and be consistent in depicting the crime scene. The final results of a properly documented crime scene is the ability of others to take your finished work and reconstruction the events that occurred at the scene and your court room presentation. In the Scene Documentation stage there are three simple steps to properly document the crime scene.
- Written notes and reports.
Each method is important in the proper documenting of a crime scene. The notes and reports should be done in a chronological order and should include no opinions, no analysis, or no conclusion. Just the facts!!! The scene should be documented just as the investigator sees it.
The photographs should be taken as soon as possible, to depict the scene as it is observed before anything is handled, moved, or initiated into the scene. The photographs allow a visual permanent record of the crime scene and items of evidence collected from the crime scene. There are three positions or views that the crime scene investigator needs to achieve with the photographs. Those views consist of overall scene photographs showing the most view possible of the scene, mid-range photographs showing the relationships of items and a close up of the item of evidence.
A close up should be taken of items that have serial numbers, tags and vin's. All stationary evidence where the photograph will be used to assist in the analytical process should be taken using a tripod with the proper lighting techniques for creating any needed shadows. A second photograph adding a measuring devise should be taken of items where the photo will assist in the analytical process.
Sketching a crime scene
Sketches are used along with the reports and photographs to document the scene. A crime scene sketch is simply a drawing that accurately shows the appearance of a crime scene. The sketch is simply drawn to show items, the position and relationship of items. It does not have to be an architectural drawing made to a scale, however it must include exact measurements where needed. The advantage of a sketch is that it can cover a large area and be drawn to leave out clutter that would appear in photographs.
The evidence collection or recovery step in crime scene processing is the methods, techniques, and procedures used in retrieving evidence. Patience and care are very important at the crime scene. The investigator should take the proper time and care in processing the scene. The work is tedious and time consuming.
Teamwork in crime scene investigations is essential. The entire investigation may involve many people from different organizations. Each individual has a vital role in the investigation process. Continual communication among all parties involved is paramount.
Consideration to comfort has to be given during the process stage. The investigator will continuously be in different positions and moving around. The only limits that the investigator will have during the process of retrieving the evidence will be his/her own imagination. Always make your equipment work for you, don't work for the equipment. The work done at a crime scene is very challenging. Don't just stand and speak of your work. A great investigator-technician allows their work to speak of them!!!!
Article Submitted by the Author
Article posted March 2, 2000
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