by Det. F.D. Zigan, CLPE, CCST, MCSFS, Crime Scene Investigations, Polygraph Examiner, Roswell (Ga.) Police Department
One of the many things I love about being able to work as a crime scene investigator and latent fingerprint examiner is that I get to travel to conferences, visit other agencies, and attend various schools. One common theme I see is separation of the disciplines within the arena of crime scene investigation, and the specialization of those disciplines which sometimes further separates them.
A smaller agency may only have a few crime scene technicians. Those technicians then grow within their career and specialize in different areas. One may become a latent fingerprint examiner, another may become a bloodstain subject matter expert, or shooting incident reconstructionist, but all still have to process crime scenes.
Larger agencies sometimes have a separate ID section that only analyze and compare various impression evidence, while the crime scene technicians process the scenes and document evidence within the lab. I have seen case agents or lead detectives directing the crime scene technician on what to process, take for evidence, and in some cases what to photograph. The detectives then try to utilize the information provided to formulate a reconstruction of events themselves. I have heard crime scene technicians state, “it is not my job to formulate an opinion on what happened at the scene, I just process it for evidence, collect the evidence, and write a report on what I observed and collected”. Unfortunately those observations don’t lead to a possible explanation/ hypothesis as to why or how that evidence came to be there.
There is a growing disconnect within the disciplines of what is being called crime scene processing and crime scene reconstruction. Many are overlooking or ignoring the importance of the context in which impression evidence is found. I have personally seen this play out during training classes, on scenes, and at other agencies that have requested outside assistance.
The crime scene investigator should not only be searching for impression evidence, but also observing and documenting the context in which it was found.
“Finding a fingerprint at the scene may be important, but of greater importance is the context in which we find the fingerprint. “ Bevel Gardner
Merely documenting where a friction ridge impression is found and making a same source conclusion is not sufficient enough for an investigation. The only information that has been obtained is that a particular person has touched an item at some point in time. The orientation, placement, and distortion must also be documented.
Orientation and placement is easy to document, however, understanding the distortion in a friction ridge pattern can be challenging. Understanding distortion in a friction ridge pattern can explain how an item or substrate was touched. It can also help the examiner articulate changes in the pattern such as minutiae displacement, ridge endings that now appear as bifurcations, differences in ridge counts in same source conclusions, change in insipient size and shape, and the change in appearance of secondary creases and wrinkles to name a few.
If the friction ridge pattern has been documented properly by the responding Crime Scene Investigator, then a reconstruction of the scene can now be completed properly.
In a real case example, a subject was accused of looking into car vehicle windows and attempting to pull on car door handles to see if they were unlocked. See Figure 1.
Instead of the crime scene investigator simply notating that a friction ridge pattern was located on the car window and classifying it as the Hypothenar area, the description could be more involved and state that the impression was cupped which is consistent with a person trying to shield the glare on the window so they could see in the vehicle better. There is also no real discernable lateral distortion (directional movement) which indicates that the hand was held relatively still. This is obviously not an accidental touch as some attorney’s claim. An overall photograph of the above friction ridge pattern would help the investigator put this into proper perspective as well. Taking only close ups of friction ridge evidence can be detrimental to the case if the investigator, attorneys, and juries can’t see its original location.
Another example is the simple shutting of a car door. See figure 2.
It is not hard to discern that it is highly improbable that this impression was deposited with the door closed. Why not articulate that in the report instead of just stating the impression was recovered on the car door? Another example of impressions or fingermarks being deposited while shutting a vehicles door is shown in Figure 3.
Understanding the distortion and how the impression evidence is oriented plays a vital role in either substantiating or refuting a statement given by a suspect, victim or witness.
Example: The victim stated that the suspect held a beer bottle over his head and threatened to hit the victim with it. The suspect denies the allegation and states that he only held the beer bottle normally like he would be when drinking it. A friction ridge pattern is found inverted on the neck of the bottle. See Figure 4. While this is not conclusive proof as there are multiple scenarios that could exist in which this pattern was deposited, it does contradict the statement of the suspect and can now be addressed in an interview.
Here is another example of impression evidence helping to construct a scene. The suspect stated that the female victim was not passed out from alcohol and she got in the vehicle of her own free will. Witnesses stated they observed an unconscious female being placed on the hood of the suspect’s vehicle while he opened the door to the vehicle. See Figure 4. Upon closer inspection of the impressions left on the vehicle in figure 5, hair impressions could be observed in the center of the hood, non-friction ridge skin could be observed where the approximate location of the arms would be with what appeared to be wrist impressions, a void where the victim’s shirt was located, and more non-friction ridge skin impressions where the victim’s lower back would be could be seen.
There are many more examples. So what are some of the details within the distortion of friction ridge patterns that should be understood to help put the impression evidence in context? Some of the clues that one should have a basic understanding of, is being able to recognize movement and directional indicators. One such clue is the noise between ridge marks where the furrows should be. Any noise in the furrows that is not attributed to the substrate, is usually an indicator that some movement has taken place. For examiners, this is a red flag that should prompt closer observations and the possibility of the displacement of ridge characteristics. Another indicator of movement would be the buildup of surface debris and matrix on one side of the ridge. The side with the buildup generally signifies the direction of movement. Other indicators are the compression and expansion of ridge spacing. The area with expansion would signify the direction of movement with the compression representing the trailing side. See. Figure 6 of friction ridge pattern moving in a downward motion.
Why is it important to know these indicators? The difference between being able to say the crime scene investigator located a friction ridge pattern on the exterior window of a home that the suspect stated he just looked into, versus being able to state that the suspect’s intent was to actually manipulate or open the window. See figure 6 for a case sample of an impression showing upward movement.
A discernable expansion of the ridges are observed in the upper portion of the friction ridge pattern in Figure 7 along with compression in the lower portion. There is also a buildup of matrix on the side of the ridges in the direction of the movement.
I asked Zack Kowalske a certified Crime Scene Reconstructionist through the IAI (International Association for Identification), why he thought there was a growing disconnect between the crime scene investigator, and the Crime Scene Reconstructionist. His answer was, “Because the disciplines of crime scene investigation and forensic science have evolved with such depth in their own right, a loss of translational knowledge and context has occurred. The over specialization of disciplined practitioners can at times overlook the fundamentals of the crime scene as a whole.”
So on one hand, we have some crime scene investigators who are trained to document and collect evidence only. We have latent fingerprint examiners receiving fingerprint cards and macro photographs of fingerprints whose sole job is to analyze and compare fingerprints. We have technicians processing evidence in the laboratories, and we have crime scene reconstructionists trying to make sense out of everything that was collected and documented separately.
The crime scene investigator has been trained in crime scene photography. They were taught to take overall photographs, then photographs with the evidence in context, then close up photographs of the evidence with scale. This should be done for impression evidence as well. There seems to be a disconnect between documenting physical evidence and impression evidence. It should be photographed exactly the same way. The crime scene report, when processing an item at the scene, should include the orientation of the impression as well as any distortion observed prior to lifting the print, as the process of physically lifting a print changes the print.
The crime scene reconstructionist should also be familiar with or have a basic understanding of friction ridge patterns and how distortion affects them. This would greatly help them understand the dynamics within a scene which could strengthen the opinion of the case. The reconstructionist needs this knowledge as a system of checks and balances. They cannot only rely on another’s interpretation of the distortion.
The crime scene investigator needs to understand that the roles within this job are changing as we understand more about the meanings of distortion found within a friction ridge pattern. So their methods of documenting must change and reflect that. They also need more training regarding fingerprint interpretation and how distortion plays a role in context.
How do we fix this disconnect?
The answer is not an easy or seamless one. There are also problems with inserting an opinion on how or why an impression came to be formed. Some of these issues are:
- Subjectivity: Determining the context in which a fingerprint was located requires interpretation, and different experts may have different opinions on what the context means. This subjectivity can make it difficult to arrive at a clear and objective conclusion.
- Incomplete information: An expert may not have all the relevant information to accurately determine the context in which a fingerprint was located. For example, if the crime scene was not thoroughly examined or documented, important contextual clues may be missed.
- Lack of standards: There are no universally accepted standards or guidelines for interpreting the context in which a fingerprint was located. This can make it difficult to compare and evaluate different expert opinions.
- Bias: Experts may have biases or preconceived notions about the case or the individuals involved, which can affect their interpretation of the context in which the fingerprint was located.
- Complexity: The context in which a fingerprint was located can be complex and multifaceted, involving multiple variables such as lighting conditions, surface texture, and the presence of other evidence. Interpreting these variables and determining their significance can be challenging.
It is now incumbent for the crime scene reconstructionist and the crime scene investigator to understand what role the context of impression evidence plays in an investigation. Being aware and understanding that that issues listed above exist and more crossover training to further understand what each job needs might be a good first step. However, I believe awareness that fingerprints can offer more information than just the identification of the individual that left ii is also key.
References:
Bevel, T., & Gardner, R. M. (2019). Bloodstain pattern analysis with an introduction to crime scene reconstruction (4th ed.). CRC Press.
DeRonde, A; Kokshoorn, Bas; DePoot, C; DePuit, M. The Evaluation of Fingermarks given Activity Level propositions. Forensic Sci Intl 2019; 302:109904. http://dx.doi.org/10.1016/j.forsciint.20190109904
Dror, I. E., & Charlton, D. (2006). Why experts make errors. Journal of Forensic Identification, 56(4), 600-616.
Dror, I. E. (2016). Emotions get the better of us: The role of emotion in forensic science. Australian Journal of Forensic Sciences, 48(1), 1-16
https://www.nist.gov/organization-scientific-area-committees-forensic-science/friction-ridge-subcommittee