Cop's Best Friend
The Use of Police Service Dogs in Crime Scene Location and Related Evidence Gathering (1996)

Staff Sergeant. Robert James Wright,
Niagara Regional Police Service

For those of us who are familiar with the use of Police Service Dogs (PSDs) in evidence gathering, or "Article Search", it is certainly not a big step to think of PSDs as a possible tool in the location of crime scenes. Although dogs have been used with a reasonable amount of success over the years, it is surprising the number of dog handlers who have not ever considered using their PSDs to assist in this manner.

Crimes against persons often occur in one area and the victim either escapes or is allowed to leave. The trauma, shock and general confusion related to the incident makes it difficult for the victim to located the scene. In cases such as a homicide, the body is often moved in an attempt to mislead police. More and more, especially in gang-related crimes, in some of these cases, investigators may be able to gather some intelligence in regard to where the crime could have possibly occurred, and this is where PSDs are able to help. in many cases, the PSDs are able to go into an area and pinpoint the scene for investigators. For those dog handlers and trainers who do not include "Article Search" in their programs, "Tracking can often be equally effective in locating a crime scene with a PSD.

Those canine teams that are capable of both behaviours (Tracking and Article Search) have two weapons at their disposal in their attempt to locate a crime scene. In those cases, the dog handler can decide which behaviour to use, depending on the intelligence he gathers as well as the environment and other related considerations such as time frame, weather and contamination. In some cases, the combination of the two behaviours will allow the canine team to be successful.

Simply stated, when using the "Article Search" behaviour, you are attempting to locate the crime scene either by the presence of human scent on an article or articles that were left at that location by either the perpetrators or the victim, or the concentration of human scent at a particular location caused by the transfer of human scent to that location during the commission of the offence. In the "Tracking" behaviour, you are attempting to locate a trail of scent -- whether it be human, ground or artificial. The trail may either be leading to or from the scene; however, it may allow the canine team to locate the crime scene.

In my best attempt to demonstrate the value of using PSDs for the location of crime scenes, two recent cases are described in which PSDs of our Canine Unit were used to successfully locate crime scenes. The first is an example of the successful use of the "Tracking" behaviour by a PSD to locate a crime scene following a violent sexual assault. The second example is the successful use of the "Article Search" behaviour to locate a crime scene following what is generally referred to as a date rape. The success of a PSD to locate a crime scene, as in all canine work, is a combination of abilities of dog and handler working together. The handler must gather as much intelligence as possible and be able to interpret the dog's actions to successfully locate a crime scene. 

Case Study #1

Shortly before six o'clock in the morning on a warm spring day, a fifteen year-old female rower was walking down a quiet road en route to the pond inlet where her group of high school rowers were practising. Without warning, she was accosted by a male who dragged her up a fifteen-foot incline into the woods where he sexually and physically assaulted her. At the conclusion of the assault, she made her way out to the gravel road where she was found by other rowers, at least one of whom entered the woods in a attempt to locate the suspect. Although no one knew at the time, a serial rapist had just committed his first offence in our jurisdiction.

The Canine Unit was not called to the scene until 8:20 am -- over two hours after the assault. The female victim could give little idea to the investigators where the attack had occurred. The investigators believed that some of the victim's clothing was still in the bush and hoped to be able to collect trace evidence if a scene could be located. With over one hundred acres of bush in the area, it was hoped the dog could save the Police Service both time and manpower in locating this crime scene.

The Canine Officer noted that the steep bank where the victim had been dragged was not a normal route for pedestrian traffic. Although the track had been contaminated by at least one other rower, there were posse 'bly three tracks leading to the scene; the victim herself on the way Out of the bush, the perpetrator on his escape from the bush, and the most dramatic or strongest scent would most likely be the original track of both individuals from the road to the scene of the attack. Both the attacker and victim would be producing large amounts of human scent from their physical exertion, as well as fear and other adrenal-related secretions. Additionally, the ground scent should be the greatest on the track because the victim was dragged, causing the most ground disruption and related chemical breakdowns that create scent patterns. The handler also knew that the edge of the bush line itself would be excessively contaminated by both police and civilians who had walked along the edge of the bush. There was also little or no wind to affect the track.

Acting on this information, the handler prepared the dog to track as the best possible chance of locating the crime scene. At the time of the attack, the victim had been walking in a easterly direction. The at-tacker had pulled her up the bill in a northerly direction; the exact point of the attack was argued within an area of about fifty yards. Therefore, the handler started the dog about twenty yards further west than any of the witnesses suspected to ensure finding the track. He also started the dog about a third of the way up the hill to avoid possible contamination from the person who claimed only to have stood on the road. The dog handler quickly started working his PSD in a easterly direction. After about forty yards, the PSD cut a track that ran north up the hill, through the wood and into a clearing where the track headed west back into another bush area and then made its way into another clearing. It quickly became obvious that the dog had done his job.

In the clearing, in plain sight, were a white sports' sock and a young girl's undergarments. After marking the scene to return later, the canine handler then attended the start of the track and led officers from the Forensic Services Unit to the crime scene. Using their expertise, they were able to obtain traces of semen at the scene. This sample was later used for DNA matching with the perpetrator and was part of the evidence provided at his Dangerous Offender Hearing.

Case Study #2

After an evening of heavy drinking at a local bar, a middle-aged female accepted a ride from a man she had met at the bar that evening. They stopped and picked up a couple of submarine sandwiches, so she had little reason to be suspicious when he made a left turn off the road and drove the pick-up truck up a rural laneway. To quote the victim, it was at that point that "he turned nasty". The victim was forced into the bush where she was sexually assaulted over a period of three hours. At the end, the perpetrator not only drove the victim home, but asked for her phone number.

Upon her arrival at home, she immediately called her daughter who rushed her to the hospital and called police. Adding to this victim's credibility was the fact she suffered from a medical condition that prevented her from engaging in normal sexual relations. Her body was incapable of producing lubrication and she was required to use a medication prior to engaging in relations.

The problem facing investigators was not only the fact that the victim had been drinking heavily, but she had little recall of the location of the attack. She simply knew the name of the rural road the perpetrator was driving on when he made a left turn and drove a short distance up a laneway before pulling to the right and stopping, The investigators had little to go on, as there were at least six possible left turns to be made off that rural route. As in all cases of date rape, the investigators would require as much evidence as possible for a successful prosecution. The investigators called in the Canine Unit in hopes that by location the scene, there would be physical evidence that would help show that this was not an act of consensual sex.

By the time the Canine Unit was called in at least five hours had expired since the conclusion of the attack. The Canine Handler had the following intelligence to work with in deciding how to best deploy his dog in an attempt to locate the crime scene. It was a clear and mild day, the area was rural, and contamination should not have been a concern. As well, the victim believed that she had lost an ear-ring during the assault, and thought that perhaps the perpetrator may have lost something as well. The perpetrator was also a very heavy smoker and had smoked during breaks in the assault; therefore, there should have been a number of cigarette butts at the scene. There may also have been articles of garbage related to the submarine sandwiches they had purchased prior to the assault. Most importantly, the assault itself had gone on over a period of hours and the transfer of human scent in this area would have been the most significant. Acting on this information, the Canine Handler decided his best course of action would be to use the "Article Search" behaviour in this case.

The handler therefore, decided to drive to each possible site and walk his dog up each possible laneway. After getting a mental picture of where a pick-up truck may have likely parked, and acting on the victlm's estimate that the attack occurred within twenty feet of the truck, the handier worked the bush line in each area twenty yards in front of and behind where a truck could possibly have parked. Since the handler was hoping to recover evidence, the PSD was worked on a thirty-foot line to prevent from retrieving an item that may have required expert examination. At all times, the handler was looking for obvious signs of the vehicle, or items that would suggest that the assault had occurred there. Although the wind was minimal, the handler still had to take it into consideration and work his dog into the wind as much as possible. "Murphy's Law" played a role in this case, as it was not until the sixth possible laneway that the Canine Team's perseverance would pay off. While working the dog in the same manner as the previous tries, the handler finally saw the heads-up reaction he anticipated from his dog. Although there was no visible evidence that anyone had entered the bush at that point, he allowed the dog to enter. Once inside the bush line, the dog immediately went toward a submarine wrapper about twelve feet into the bush line. The handler stopped his dog from retrieving it and pulled hii-n to his side and praised him. Near the wrapper was a cigarette butt and the handler knew the PSD had done his job.

After returning the dog to the patrol vehicle, the handler showed investigators the scene. Not only were the wrapper and cigarette butt in plain sight, but also a great deal of now-obvious ground disturbance and other evidence, including some human hair. At that point, it was time to turn the scene over to the Forensic Services Unit who were able to find more evidence in the area and also photograph and otherwise record the scene for court.

In this case, the evidence found at the scene was almost secondary to the scene itself. The question that kept screaming out was why would anyone have consensual sex in this location. It was very obviously dirty and uncomfortable and there were alternatives in this rural area, including the pick-up truck itself. These are two examples of how easy it is for PSDs to play an important role in the location of a crime scene and related evidence gathering. These were not difficult tasks for either the dog or handler and most competent dogs trained in "Tracking" and/or "Article Search" would have been successful in these cases. In these two examples, it was simply a matter of giving the Canine Teams the opportunity to work these cases.

What these cases do show is that a Canine Handler can use the intelligence gathered and their dog in a duty they are trained for and be successful in the location of a crime scene. Therefore, without making any real change to your Canine Unit, you have one more way in which your resources can better serve your police agency.