7.3: Responsibilities of the crime scene technician

The primary ambition of the crime scene technician should be: the proper documentation of the scene; the proficient and legal collection of all items of evidence within the scene; the maintenance of the chain of custody of the evidence; and the ability to articulate the steps taken, including scientific methodologies, evidence collected, photographs captured, measurements documented, diagrams made, and to paint a visual picture of the scene to the jury, judge and attorneys during courtroom proceedings.

When arriving at the crime scene, the crime scene technician, or analyst must first determine that the scene is safe to enter, for themselves and for their team members. The technician should then make a quick assessment of the scene for perishable or fleeting evidence and for any hazard that might alter or damage the scene before it can be processed. Once satisfied that the scene is safe and not in danger of losing valuable evidence, the technician must then determine the crime scene perimeter by speaking with the first responder on scene to determine what actions they saw, what evidence they noticed and where they discovered victims, suspects, and witnesses. The crime scene technician should then ensure that the crime scene perimeter has been properly established, and the perimeter is large enough to contain an outer and inner perimeter. This is generally accomplished with crime scene tape. It is always best to have a large outer perimeter that will keep the media and on-lookers far from the actual crime scene but will also maintain a containment of the areas of ingress and egress. Crime scenes can be made smaller, but they can ever be enlarged, and therefore the larger area would be contaminated prior to any items of evidence having been found. Once the outer crime scene perimeter has been established, the technician can designate a primary crime scene, which includes the actual crime scene itself, and a staging area for equipment that is just outside of the primary crime scene. It is important to maintain proper protocols for the mitigation of contamination for equipment remaining in the staging area and for equipment being utilized within the primary crime scene perimeter.

Scene security is important to the safety of the crime scene team and for the protection of the scene and the evidence it contains. Therefore, it is a good idea to arrange for the posting of armed officers outside of the outer crime scene perimeter to control the crowd, the curious, the media, or the return of the suspect(s), which has happened to more than a few technicians.

The crime scene technician should immediately determine if the suspect(s) is in custody or is at large, if the victim is deceased at the scene or if life-saving efforts are on-going, or if not to ascertain where the victim(s) has been taken. Should an eyewitness be available, the investigator should briefly interview them focusing on what they saw, smelled, and heard. It should be noted that a crime scene technician will ask different questions than a first responder. The first responder is intent upon locating the victim, additional victims, suspects, and other eyewitnesses, and perhaps a perfunctory overview of what happened. Amongst the information the crime scene technician is most concerned about is what happened and where, who was in the crime scene before, during and after the event, what weapons were used, what was touched by the suspect, what injuries were sustained by the victim, was the suspect bleeding, and in which direction did the participants arrive and depart. If possible, it is imperative that the technician also talks to any responding medical personnel who remain at the scene. If the suspect is in custody, the crime scene technician should make recommendations regarding the collection of the suspect’s clothing, the bagging of hands to preserve transfer evidence, the collection of gunshot residue specimen, photographing injuries, or the swabbing of hands for DNA.

Once the initial information gathering interviews are finished, the technician should meet with the other members of the crime scene team outside of the secondary crime scene. The team should be given assignments such as scribe, photography, diagramming and measurements, evidence collection, and other duties. They can then don protective coverings and make their initial examination of the crime scene. At this time, the technician or analyst will determine the appropriate path through the scene that will prevent destruction of evidence and ensure that each member adheres to the selected route. It is essential that the crime scene and evidence are not disturbed and that nothing is touched or moved.