Minimum items of protective equipment:
- Latex gloves – key tool, allows the investigator to interact with the scene and evidence without leaving DNA and fingerprints.
- Facemask – respiratory protection where risk of exposure could be dangerous, in the context of modern events, also vital for health and public safety reasons.
- Googles or protective eyewear – Eye protection in cases of biological or chemical hazard, where risk of exposure could affect health.
- Protective clothing – depending on the type protective clothing both maintains safety for individual, prevents the investigator from contaminating the crime scene with external material or DNA.
- First-aid kit – while not directly protective equipment, vital for treatment of any injuries or risks stemming from hazards.
Most common types of hazards:
- Bio-hazards – biological material such as bodily fluids that may contain bacteria or contaminants – gloves, protective clothing
- Chemical hazards – artificial and chemical substances that are unsafe – gloves, strong protective gear (hazmat suit), face mask, protective eyewear.
- Physical/environmental hazards – situational or direct threats ranging from weather to poor structural integrity of a building – basic protection clothing, mask and googles if necessary, gloves.
If one reaches a crime scene where there are evident or known hazards, and the protective equipment is missing, then proceeding with the investigation is not recommended. This is both due to the need of protecting the personal safety of the investigator, as well as to avoid damaging or contaminating a delicate crime scene that is affected by hazards already. An example is a that a crime is committed in a potential home meth-lab where there is a lack of proper safety precautions. Inhaling fumes from chemicals in the drug creation could make a person ill. This type of investigation would require at the very least protective eyewear and a respirator mask, likely a full protective suit. Unfortunately, there are no good alternatives for the equipment in such a scenario, as anything lesser of a protection poses a risk, and while there may be respirators present at the crime scene, these would all be considered evidence. If available, an investigator can use some sort of drone to potentially explore the area to identify risks and locations.
Safety and Securing the Crime Scene
An outdoor crime scene is extremely vulnerable to loss, contamination, and damage. Furthermore, environmental elements can also quickly impact evidence, particularly biological. Individuals that are present at the scene can alter, remove, destroy, or contaminate evidence both intentionally and unintentionally (National Institute of Justice, n.d.). In the scenario this was evident by an individual running away with an object – which may have been a key piece of evidence in the investigation. Investigators can avoid this problem with the aid of law enforcement when arriving at the scene, with established protocols. The approach is to identify all persons present at and around the crime scene and control their movement by restricting movement, location and activity whilst maintaining safety. Also, proactive identification and establishment of crime scene boundaries is crucial. Boundary determination is based on location, type of crime, and scope of the crime scene. The area should extend outward from the focal point of the crime, and include points of entry and exit, as well as where evidence could have been moved. Physical barriers should be set up as soon as possible, and all people movement should be documented (Reno et al., 2000).
During the process of crime scene investigation, detailed notes are being kept with the times and dates of actions. Arguably, it is impossible to avoid all potential contamination or physical manipulation of the crime scene. Therefore, forensics typically controls and records ongoing contamination to avoid damaging the forensic integrity. All witnesses, suspects, responders, and investigators are typically required to record and make a statement regarding their actions to identify contamination to the scene (Gehl & Piecas, 2017).
Therefore, in the scenario, it is vital to immediately note the occurrence in official proceedings and notify other investigators, as well as photographers and forensics. If possible, to make note which footsteps were made by the investigator, and not use this as potential evidence. The investigator would likely have to submit their shoes into evidence, at which point forensics can use detailed analysis of footwear track examination to match the shoe to the bloody footprints. At this point, these would be marked and excluded from the subsequent investigation process.
Outside of traditional security measures described earlier, a common method from such occurring is once the perimeter is locked down, a designated pathway is established. It is commonly done by the first investigator to re-enter the crime scene. Prior to doing so, the investigator takes a photograph of the area where the path would extend, and then dressed in sterile apparel would mark the floor with tape. This is known as the pathway of contamination and follows a trajectory which avoids direct contamination of the crime scene elements (Gehl & Piecas, 2017). Of course, other warning measures such as signs and maybe even electronic proximity alerts could be useful to remind personnel to use sterile apparel and pay extra careful attention may be appropriate.
The first step would be to isolate and secure the scene of the crime. Using physical barriers such as perimeter tape, identify an appropriate range around the scene to isolate, with sentries placed at all entrances. Processing the scene, it is critical that one other environmental factors such as weather or further use of chemicals nearby, contaminate the scene further, therefore the use of artificial covering, at least over the area of the body, may be necessary. Outdoor crime scenes need to immediately document the location geographically, both via GPS coordinates as well as relative to known geographic markers such as roads, mile marker, or even a fixed object in an open field (Gehl & Piecas, 2017).
Investigators and forensic technicians will have to wear protective clothing to the scene, not only for the preservation of few pieces of evidence that may be left, but also for their own safety as agricultural chemicals may be potent when initially sprayed. Protective chemical suits may be required, with respirator masks to prevent inhalation of pesticides. Traditional gloves, footwear protection, and goggles are relevant in this situation. The use of protective gear ensures that investigators do not bring any foreign debris and chemicals, especially in an already complex outdoor scene, as well as not accidentally removing or manipulating any evidence. In terms of specialized equipment, it may be necessary to bring additional tools for measurements and tracking, highly accurate devices that can contribute to forensic analysis among all the “noise” of the outdoor environment. Furthermore, biohazard protection tools and storage, more complex photography equipment is likely necessary for outdoor image capturing.
It is very difficult to document an outdoor crime scene, especially when it is known that it has already been contaminated. There are a myriad of virtually unpredictable factors to consider. Some of the most important elements to consider is defining the context of the outdoor scene. These include: primary objectives of interest (physical evidence, body, associated items), surrounding biotic, geophysical, and climatic features (anything ranging from soils, water, temperature, humidity, etc.), and finally, the passage of time (temporal context) should be documented. Once evidence is removed from the scene, context is effectively destroyed, so it is vital to document these details via notes, images, and maps to collect valuable information that ultimately answer the more concrete questions such as who was involved and how was the crime committed (Dirkmaat, 2012).
Dirkmaat, D. C. (2012). A comparison to forensic anthropology (1st ed.). Blackwell Publishing.
Gehl. R., & Piecas, D. (2017). Introduction to criminal investigation: Processes, practices and thinking. Justice Institute of British Columbia.
National Institute of Justice. (n.d.). Outdoor crime scene.
Reno, J., Marcus, D., Robinson, L., Brennan, N., & Travis, J. (2000). Crime scene investigation: A guide for law enforcement. U.S. Department of Justice Office of Justice Programs.