Crime Scene Investigation
Crime Scene Team
The purpose of investigating an incident is to determine if a crime has been committed, and, if so, to bring to justice the person or persons who committed the crime. The investigation begins the moment the incident is reported by either a victim, a witness, or by an officer who comes upon a crime by chance. It ends with the final verdict of the court or jury.
A crime scene team is a group of professional investigators, each trained in a variety of special disciplines. The common goal of the team is to locate and document all the evidence at the scene, each member must be allowed to work the scene independently of the others involved and to challenge the others assumptions. The most important factors to successful investigation are planning and teamwork.
Investigating A Crime:
the team approach to crime scene investigation begins well before the crime. The planning begins with a procedure agreed upon by all the team members. Training for each member is a must, but perhaps more important is an understanding of exactly what is expected of each member at the scene and at the autopsy. The scene procedure can vary depending on the agency and the crime. The plan must anticipate problems and provide answers to specific questions such as:
* How big is a crime scene?
* who should be at the crime scene?
*who should be in charge?
*what should be done to process the scene?
* Who should do the work?
The Scene of the Crime
The scene of the crime is thought of as the place where the crime is committed. But a simple crime may have numerous locations to search where events took place. Consider the first scene where evidence is located the primary scene, even if it is not the most significant and other subsequent locations as follow up or secondary scenes.
In general, the primary crime scene can be legally searched if the crime is committed in a public place. If the resident calls for help at his or her dwelling, or if the evidence is in plain view while an emergency condition exists in a dwelling or place of business.
All other situations including many secondary scenes may involve a right to privacy issue and require careful analysis by the team before they proceed with a search.
The police may respond to a citizen's calls for help in the home only to discover, as the investigation progresses, that it looks more and more as if the reporting party committed the crime. The team leader must inform the suspect of specific rights to remain silent and so forth and that the suspect may withdraw the original permission to search.
The scene process applies once an emergency in the home or place of business is over or under control. Although legally inside the scene, the team has to re-examine its authority to search for anything other than what was in plain sight, or the exact point of the emergency. But the team cannot legally look into other rooms or places unless there is sufficient cause. For example, a trail of blood leading into other rooms indicating other possible victims.
The right of privacy may be an issue even when the victim is deceased. For example, a landlord calls to report a murder in an apartment rented to the victim. Before evidence is seized, the landlord should sign a statement indicating that there are no co-tenants and giving permission to search. If there are co-tenants they must also give permission. If they are not available for any reason, a search warrant is required, since the co-tenants may turn out to be a suspect in the crime.
A Crime Scene Defined:
A working definition of the crime scene, primary and secondary, is anywhere evidence may be located that will help explain the events. Frequently, the suspect's vehicle, home, and place of business are also scenes. In any death investigation, the autopsy should always be considered a scene to be attended ideally by the same investigators who worked the original scene.
As a group, the crime scene team will assure the documentation of the scene by:
1) Their written or electronically recorded notes.
2) Photographs of the scene and all observed evidence.
3) A scale diagram, a drawing, of all the pertinent items at the scene.
4) Collecting, marking, packaging, and preserving all items collected.
Processing a Scene
Evidence collected at the scene may serve several purposes:
1) Prove that a crime has been committed.
2) Indicate key aspects of the crime.
3) Establish the identifies of the victims or suspects or determine what kind of investigation must be conducted and see how they corroborate(or not) any testimony given by witnesses.
5) Help to exonerate a suspect who is innocent
6) Provide leads for further investigation
7) Pressure suspects into giving confessions
11 steps are required to document a crime scene.
Step 1-Evaluate the nature of the scene. The evaluation begins with the first officers, but it is actually an on-going process continuing each time a new team member arrives at the scene and ending only when the last one leaves.
Step 2--Protecting the Scene. It has a far-reaching purpose to establish and protect the integrity of any evidence located at the scene. To the criminal justice system in general, and to the trial court specifically, the integrity of all evidence is crucial.
Before any item collected by the crime scene team is admitted as evidence, it must meet standards. It must be legally obtained, it must be relevant to the crime, a witness must identify the item describing its origin and the chain of possession must be demonstrated, that is everyone who handled the item in any manner must be available to testify. This includes finding, transporting, storing or analyzing the items.
Protecting the scene and the evidence it contained is therefore a constant process, also begun by the first officer at the scene, the time the scene is first evaluated, and continuing for as long as it is under the control of the authorities. The protection of the scene lasts until the entire team agrees that there is nothing remaining to do, and it can be surrendered back to its normal purpose.
Processing a scene may take minutes, hours, or days.
Steps for Processing a Scene:
* The first officers must notify the watch commander of the conditions at the scene, indicating the necessity for a team investigation, or other issues, such as a search warrant.
* Members of the team are notified of the circumstances of the scene and respond to the location. The team may be a predetermined group, or may be selected from a list of on-call personnel.
* The first police personnel at the scene take control of it and make it clear to all others in, or near, the scene what they are to do. No one already at the scene should be allowed to leave without being properly identified. The officer in charge of the emergency team must create a list of everyone known to have been within the boundaries of the scene up to that moment.
* The team members should establish a command post just outside the entrance and boundaries of the scene. This can be as simple as a card table or as elaborate as a fully equipped mobile communication center and/or laboratory.
* At the command post they must initiate an order of entry form, that is a sign-in sheet that every person entering the scene signs indicating time of entry and purpose for being there and describing all items they located and removed from the scene. This is the first step in the chain of possession of the evidence. They must require that everyone who enters the scene that is beyond the command post write a supplemental report indicating what they did at the scene.
* Everyone other than personnel who are protecting the scene should be escorted to the command post.
* Upon arrival, the investigator in charge, based on all the available information, should determine if a search warrant will be necessary and, if so, begin the process of obtaining one.
* Once all the team members are at the scene, the investigator should brief the group with all the known information such as changes to the scene made by the emergency team. The team should determine at this point if a larger area should be protected.
* An entrance/exit, the pathway in and out of the scene. The path clearly marked with rope or tape should be selected by a joint decision of the team. The path, as roundabout as it need be, is chosen to avoid traffic though areas of obvious or potential evidence. The path may be altered as new items are located or when processing in a specific area has been completed to the teams satisfaction.
* The team members entering the scene should wear clearly marked garment distinguishing them from other personnel working around, but not in, the scene.
* The investigator should hold mini-meetings to determine the progress of the team.
* Before the team surrenders the scene, the investigator should hold a team critique to verify that everything has been completely documented.
Step 3--Surveying the Scene. The purpose of this step is to gather enough preliminary information to begin the most logical approach to processing the scene. With an unaltered scene as a continuing goal, the survey is best begun at the agreed upon entrance.
Key questions to be considered by the team at this point are:
* Is there evidence of the suspect's point of entry, point of attack or point of exit
* Does the suspect normally have access to the area?
* Was the suspect still in the scene or allowed back into the scene?
* Does information offered by the victim, witness or suspect make sense at this time?
Under no circumstances should known suspects or any of their belongings be escorted into the scene, even if they admit to having been there earlier.
Step 4--Photographing the Scene. Three categories of photographs should be taken at the crime scenes.
1) Overall views, looking into and out of the entire scene.
2) Orientation view of items of evidence.
3) Close-up views of each piece of evidence. These photographs provide a history of the conditions at the scene, a view of the location of each item of evidence, and a method of identifying the items for future reference. The team members will use the photos as an investigative tool to reconstruct the events or to refresh their memory of the scene at a later date.
Eye-level photographs are the most common but other positions or angles may be advantageous.
For the orientation photographs, the photographer usually take eye-level views since their purpose is to identify the relative location of evidence collected
Step 5--Sketching the Scene. The crime scene sketch is a record of the exact location and relative position of all the relevant items at the scene. The distances recorded by the evidence investigator at the scene may be used later to prepare a formal crime scene drawing to educate decision makers. These sketches and drawings are two-dimensional and are presented in conjunction with the scene photographs.
The rules for sketching a scene are as follows.
* The investigators must make the measurement carefully. That is within the limits of the devices used such as tape measures, rulers, or measuring wheels. It is not acceptable to make estimates, pace off distances or rely on someone else's undocumented information.
North must always be indicated and should be at the top of the paper. the rule of North. North must be determined by the use of a compass at the scene.
* The scale must be indicated somewhere on the document even if the drawing is life size, as in a one to one drawing of a blood pattern.
* The sketch and the drawing must be identified with key information such as the case number, locations represented, a table of contents(a list of items shown), the name of the person making the sketch, and if the final drawing is done by another person or artist, the name of the person who verified all the details. The witness must approve the drawing prior to taking the stand.
Irrelevant items are not included in the sketch. The photographers will reveal everything at the scene so it is unnecessary to include uninvolved items even though they are in the middle of the place. The simple rule is, if the thing is the evidence or the heart of the evidence and will be collected, it goes on the sketch.
* All items must be located on the sketch by the measurement from at least two permanent fixed points that can be relocated if the need arises. The three measuring methods used most frequently are the coordinate system, the polar method and triangulation. Measurements must be made from some fixed point to the location of the evidence. Anything permanent may be considered a fixed point.
The coordinate system, as used in mathematics and computer science, located a point within a space using two measurements. Almost all crime scene sketches are prepared using the coordinate method.
The polar method provides for the two fixed measurements to be made conveniently by allowing the team to arbitrarily select a center point for their crime scene regardless of the location.
Step 6--The Limited Search. After the arrangement and location of all the evidence and the relevant items in the room have been thoroughly documented, the first nonemergency alterations to the scene are permitted.
Step 7--Close up Photography. If the photo is to be used for comparative purposes, the frame must include a measurement scale of some type such as a ruler.
Step 8--The complete Search. At this point, every apparent item of evidence has been documented. The complete search is initiated to locate less obvious evidence.
For indoor crime scenes, there are only three absolute considerations.
1) Always search crime scenes with adequate light. Major scenes deserve to be searched in the daylight
2) Remember to look in all directions, look at the underside of furniture, at the backside of standing things. Open doors must be shut and the reverse side examined.
3) Always lake a close look at the area outside the designated crime scene. At least a few feet in all directions around the outer perimeter.
Step 9-Collecting the Evidence. This step is also the first link in the chain of possession. The courts demand that evidence be presented in its most original form, the best evidence rule.
Step 10--Completing the Measurements. Any measurements that could not previously be made without altering the scene or moving the evidence can now be made.
Step 11--The Team Critique. Members of the team individually review what they have done at the scene.