Human Remains Detection with Cadaver Dogs
The latest Police Canine Detector Specialty
Officer Allen Lowy
Officer Pat McAlhany
Miami-Dade Police Department
Canine Unit
The working police canine has become an integral part of law enforcement. For centuries now, dogs have had a well established place in law enforcement. Working a loyal members of teams with their human partners, they have proved to be invaluable in such vital areas as explosive detection, narcotics detection, and searching for criminals as well as lost or missing persons. In many ways, dogs contribute more to achievement of law enforcement objectives than sophisticated law enforcement technology.
Despite the long and distinguished history of canines in law enforcement, their capabilities and applications are still emerging. One relatively new area of specialization, that is very promising, involves the use of canines to detect the presence of human remains. Resourceful canine handlers have found that dogs can be trained to detect human remains long after death, despite burial or attempted concealment. Trained dogs are able to distinguish between human remains, animal remains, and a wide range of other odors that would normally be expected to distract them. Thus, their ability to distinguish between sources of similar biological odors enhances their application in the area of Human Remains detection (HRD).
Canines that detect human remains, commonly referred to as cadaver dogs, have been minimally represented in the law enforcement canine population across the United States. For a variety of reasons this canine detector specialty has not been given the attention that is afforded both explosive and narcotics specialties. These departments continue the age old practice of assigning all aspects of death investigations to Crime Scene and Homicide units, without realizing the additional capabilities that a trained HRD canine team would bring to their scenes where a corpse or the remains thereof must be located. The remaining obstacle generally involves the complexity and type of required canine team training.
In the final analysis, for many agencies, it is not feasible to have an HRD program. Weighing the cost of training, canine purchase and care, as well as the cost of vehicles and equipment with the actual need, it becomes clear that the addition of another narcotics or explosive detection team is more practical. The probability that the HRD team from a nearby, larger department may be available to assist with the occasional search is further justification for not adding HRD specialist. On the other hand, departments that can see their way clear to add an HRD program gain valuable, readily available investigative tool.
A successful HRD program must begin with motivated personnel who readily accept the fact that they will be working and training under morbid scenarios. While the exciting prospect of locating an explosive device, a large cache of narcotics or apprehend a fleeing criminal easily attracts most police canine handlers, few have the requisite interest or motivation for dealing with all phases of human decomposition and disarticulation that will be encountered by the HRD team. The demands placed on the canine handler specializing in human remains detection go beyond dog training and include studies in Forensics. awareness of basic human anatomy and knowledge of the rate of decomposition of human bodies when subjected to varying disposal methods (i.e.: soil type, temperature, scavenger activity, presence of water) and how to conduct "field craft" (i.e.: assessment of a potential grave site or disposal area based on the knowledge that certain changes in the soil, plant life and insect population indicate the possible presence of human remains) must be demonstrated by HRD canine handlers desiring to be successful in the specialty. Once the prospective canine handlers have been chosen, it is necessary to identify suitable canine partners.
Selection of a canine for HRD involves testing (as required before selection for any detector specialty) of the animal's motivation and demeanor as well as its attraction or aversion to odor of human remains. As is the case with potential human team members, not all working police canines are well suited for human remains detection. Use of valid selection criteria for HRD teams is of paramount importance if a successful training experience is to occur and yield a qualified HRD canine team.
After recognizing the need for a HRD program and selecting team members, the focus turns to training, to prepare the teams for deployment during actual investigations. A review of an agency's needs that involve locating and recovering deceased persons will provide useful data which can be used to create training situations that will be similar to real death investigations that HRD teams will become involved in. Training must be designed to include scenarios that closely resemble cases that the HRD team might be expected to handle. Training situations must simulate searches for bodies or the disarticulated remains thereof that have been disposed of or concealed by burying, hanging, placing in water, in vehicles, in structures or under structures, in the environment in which the canine team will normally operate. Effective training must prepare HRD canine handlers to take into consideration the variables of temperature, soil types, terrain, surface and ground water movement and their impact on decomposition rate and availability of the odor of human remains. The variety of handler skills developed during training, combined with the olfactory abilities of a specialized canine partner produce a "team"....
Preparing the police canine specialist for the task of recognizing the odor of human remains and locating its source is an area of uncertainty for many departments because of the mystique that seems to surround the specialty. In reality, training protocols for HRD canines involve application of the same Pavlovian techniques used to motivate a dog to perform any task or trick; familiarize with the behaviors required for the task or trick, creation of opportunities to perform the task or trick and presentation of a desirable reward to motivate the dog to perform the task or trick when directed to do so. The specialized training of the HRD canine begins with the repeated presentation of the odor of remains which is followed by teaching the dog to consistently display a trained alert behavior when encountering the odor. The motivation for the desired canine behavior is the reward which the handler consistently provides when the dog correctly performs the required tasks.
Once the human and canine team members have completed the basics, its time to add variables such as those that will be encountered beyond the controlled training environment. Introduction of the potentially distracting odors of garbage, food, and deceased animals becomes part of the curriculum along with searches of areas where no "odors" have been placed. Initial and ongoing training must include these "proofing" exercises where the team is presented with search areas that contain animal carcasses as well as search areas that have neither dead animal nor human remains odors present. Preparation for real searches includes the realization that not all areas searched are going to yield human remains odors thereof. Thus, a successful training program constantly challenges both the human and the canine team members with reality based, learning experiences..
The completion of preliminary, intensive, HRD training equips the team for the responsibilities of their specialized, investigative assignments. During actual field work, the primary responsibility of the canine handler is to evaluate the circumstances surrounding a case; gather the necessary information and combining it with their specific training to define the search area and formulate a search plan to insure that the dog has the best opportunity to locate the odor of the human remains. If the handler fails to define the search area or make the odor available and the canine never gets near the area where the human remains odor is present, then the handler must accept the blame for the teams' failure. A search is not merely walking around and permitting the dog to randomly sniff an area, it involves careful fact gathering, analysis and appropriate use of tools that are employed to make existing odor available for detection by the dog. Some of the tools that might be employed to increase the availability of odor include venting rods, power tools, a machete or a boat, etc.. Precise identification of a search area is imperative and should include a written record of any procedure used during a search.
Each investigation must be handled as though the area(s) to be searched will be a crime scene. Not only must an accurate written record of the HRD team activities be made, but the team must conduct their search so as not to disturb or alter crime scene evidence. For example, some of the techniques used by conscientious HRD teams include use of canines that display a passive trained alert behavior when locating the odor of human remains. The passive response might consist of the dog assuming a supine position or sitting as close as it can get to the source of the odor. The passive alert involves no action on the part of either team member that would destroy evidence. It is also critical that the HRD team recognize the functions of other specialty units involved as a death investigation progresses. Not only must the team endeavor not to damage anything during their part of the investigation, they must utilize flags or other recognizable means of marking sites requiring further investigation and communicate their needs and methods clearly. A written record as well as a verbal explanation of the HRD teams methods or findings should be provided to the lead investigator(s) and crime scene specialist. Mutual respect must be practiced by all investigative counterparts if a search is going to be fruitful and evidence obtained therefrom be of value in future court proceedings.
To fully appreciate the HRD teams, it is necessary to learn as much as possible regarding the circumstances surrounding investigations in which they are asked to participate. Bodies buried, disarticulated bodies, bodies submerged in water, or hidden in vehicles or structures have been efficiently located by HRD teams. HRD teams are equally important in revealing that there was no odor of human remains present at a designated location, despite an informant's insistence to the contrary. "Clearing" an area by determining that no odor of human remains was available enables the investigation to move on to other venues. HRD teams do not work miracles and in some cases, foot searches have been conducted by the requesting agency following the HRD teams preliminary scan of an area. Use of credible HRD teams will contribute to the expeditious and through conclusion of most searches for human remains.
If any agency seeks assistance in the form of HRD teams, it is important for them to know the background and qualifications of the teams so that their level of expertise is established. It is important for them to ask questions and remember that there are no dumb questions. Inquiring of the FBI or State Law Enforcement Agency as to their recommendation of HRD teams within the state is also advisable. When speaking with the HRD representative or supervisor, it is important to ask questions regarding their training, training certifications and cases handled. The HRD team must be able to produce their training records, and search records. Remember that the prospective HRD team's credibility in court (i.e.: case reports, accurate training records and experience) may be a critical issue should the investigation that the HRD team's assistance is sought for, goes to court. Prosecutors should confer with personnel from the agency's Homicide section or Crime Scene section for their input and experiences with the HRD team. Contact with the Medical Examiner's office within the jurisdiction of the prospective HRD team. This contact should reveal the presence of a solid working relationship between the HRD team and the Medical Examiner or their representatives. One of the most important resources to be developed by HRD teams is information obtained through consultation with the Medical Examiner's office.
Hopefully this article has answered some questions regarding the capabilities of and uses for Human remains Detection teams in law enforcement. Equally important is the awareness of what is required to make competent Human Remains detection teams and how to measure their value to an investigation. Human remains detection is yet another tool that can be employed by law enforcement in the ongoing effort to let the victims speak and bring criminals to justice.
Article submitted by the authors
Article posted March 13, 2000