From talking with different people and discussing agency policy and procedure, there is a great degree of variability across the United States and even the World on the subject of acceptable practices and the reporting of latent print sufficiency. Many variations exist in reports on the sufficiency of latent prints in cases where no comparisons were conducted. Sometimes, reports may include a phrase such as "3 latent prints of value were found on the lifts in Submission 1". Some examiners or agencies go on to define "value" in terms of "identification purposes" or "comparison purposes", but many do not thoroughly define the difference between these terms within their policy and procedure. If definitions are not available when differences of opinion occur, an agency or examiner has no foundation on which to build an argument for determining which opinion was acceptable and which was not acceptable. These concepts are further explored in an attempt to generate discussion on this issue and help agencies and examiners arrive at a consensus regarding which of these terms should be adopted, and in what situation(s) their use is appropriate.
Analysis is the first step in the ACE-V methodology. During analysis,
an examiner looks at the latent print and gathers information. That
information includes, but is certainly not limited to the quantity and quality
of ridge flow, ridge path, ridge shape, clarity, distortion, focal points,
groups of detail on which to start comparison, etc. During analysis, a
judgment determination will be made whether to keep that particular impression
as evidence in the case. This step is usually performed at a time long
before a thorough analysis of the latent print can occur under magnification in
a controlled environment. Many times, the first person to determine
whether the latent print is valuable as case evidence is the crime scene
technician who develops an impression at the crime scene. In this
situation, every piece of ridge detail developed is analyzed to answer this
question: is this impression valuable enough for a latent print examiner to
continue to the Comparison step of the ACE-V methodology?
Sufficiency for Comparison
If any piece of ridge detail that has potential for value in the comparison process is retained, only those impressions which the case examiner feels are valuable for him/her to compare are claimed as valuable for comparison by that examiner. The remaining impressions simply exist in case evidence and/or documentation. By claiming an impression, the examiner is saying "this is valuable for me to compare", nothing more. In other words, they are not necessarily saying that an evaluation of information gained during the Comparison phase will result in a conclusive determination. Rather, they are simply saying that potential exists for that possibility; therefore they are going to give it a chance by claiming the latent print as valuable for moving on to the comparison purposes.
If a comparison is conducted and an individualization or exclusion decision can not be made by the examiner, an inconclusive determination will be the result. There is no shame in this! This is one of the conclusions that SWGFAST acknowledges. There are times when, based on an impression, a person can neither be identified nor excluded. This does not mean that a conclusive decision is not possible at another time. This also does not mean that if additional prints are received, a conclusion would not be possible, or that the impression won't be valuable when compared with another person. If the examiner feels that at any time they could conduct a comparison with the best possible known impressions of any person and could possibly arrive at any conclusive determination, then the impression should be considered suitable for comparison purposes by that examiner. The impression should be "claimed" as sufficient for comparison purposes by that examiner and documented as such in the case notes according to standard department protocols.
A practical example of the use of such an impression involves a print with very limited level 2 detail, no level 3 detail, but contains reliable level 1 detail. If the impression is not retained, how could a potential suspect or victim be excluded as having left that impression? To not retain the impression is to destroy possible exclusionary impression evidence. Even if no unique level 2 detail can be observed, a latent print that is definitely a whorl pattern can be excluded as having been made by a suspect, for example, with all arches or loops. In short, the impression is sufficient for exclusion, even if it is not sufficient for individualization.
Of course, it must be remembered that "absence of evidence is not evidence of absence." Just because a latent print is excluded as being that of the suspect doesn't mean the suspect did not touch that surface. Likewise, just because a print is individualized to a suspect doesn't necessarily mean the suspect committed the crime. These two perspectives must constantly be considered when discussions of sufficiency occur. The probative nature of the evidence upon which the impression has been deposited must always be considered. Naturally a blood print on the murder weapon has more weight than a latent print in a public area.
So to conclude, if an examiner feels they could potentially arrive at a conclusive determination based on an impression, or if there is any doubt as to whether he/she feels this is a possibility, then the impression should be considered "sufficient for comparison" and it should be documented and preserved as such, if circumstances and department protocols allow. This decision serves as the foundation for additional decisions on the sufficiency of a latent impression. Without this second foundation, the possibility does not exist for the case examiner to make an identification or exclusion. With this foundation, the possibility does exist for the case examiner to make an identification or exclusion.
An impression that is sufficient for comparison purposes is always sufficient for retention as case evidence. On the other hand, impressions that are deemed sufficient for case evidence may not always be deemed sufficient for comparison purposes by the case examiner.
Figure 2: Sufficiency for Comparison forms the foundation for individualization
Sufficiency for Individualization
Proficiency levels differ based on many factors including training, experience, talent, motivation, personality and daily variables. No two people will have exactly the same proficiency level in latent print examination. In addition, the proficiency level of the same person will fluctuate over the course of their career, or even daily in some circumstances. Therefore, determinations of sufficiency for comparison purposes should not be considered static determinations. If a latent print examiner who has been trained to competency by his/her agency determines early in their career that a latent print is unsuitable for comparison purposes, few would argue they should never be allowed to re-assess the latent print after substantial continued education in latent print matters. Likewise, no latent print examiner should be expected to continually, case after case, year after year, make the same determination of suitability for comparison purposes as another examiner.
Those who demand agreement by all latent print examiners on every impression misunderstand the examination process of human examiners. On the other hand, an examiner who chronically determines impressions to be unsuitable for comparison purposes when other examiners claim and identify them may need to re-evaluate his/her proficiency and obtain additional latent print training. Such an examiner should not be surprised when his/her agency identifies performance as a problem and initiates measures to correct the problem. Nobody is in a better position to assess latent print examiner proficiency than a reviewer of cases. If one examiner continually performs below the proficiency level of other examiners in the section with regards to judging latent print sufficiency for comparison purposes, an administrative decision must be made whether to accept or not accept that level of performance. If continued operation at that level of casework performance is accepted by the agency, then the responsibility may fall upon the agency if that low level of performance results in injustice (valuable latent impressions of a suspect were not claimed as sufficient for comparison purposes).
On the other hand, examiners should never feel pressure to claim a latent print "of value for comparison" if they feel they could never reach a conclusive determination on the impression, even with the best known prints possible. The decision regarding sufficiency should be completely up to the examiner, and should be made without pressure from other examiners or supervisors. The administrative decision on whether those decisions are acceptable is up to the agency. Some sort of objective measure should be explored by the agency regarding the difficulty of impressions examiners are expected to claim as valuable for comparison purposes. In short, the agency should set the bar regarding expectations of the examiner. In addition, periodic case review should be conducted to determine whether problems exist relative to this threshold, and policy and procedure should be in place to deal with chronic under-performance in grading latent print sufficiency.
The next type of sufficiency surpasses that of "comparison" value to sufficiency for individualization. If an examiner definitely knows that he/she could make an individualization of a latent impression with a good set of known impressions, then a determination may be made that the latent print is "sufficient for identification (individualization)", and it may be documented as such. Without this third foundation, the possibility for the case examiner to make an identification or exclusion still exists. In other words, it isn't mandatory that impressions "of value for comparison" be considered sufficient for identification. But this distinction does add a level of clarification to a report for an investigator to know what can and can not be done with the evidence. With this third foundation, investigators can better know that the impression could be identified if they obtain good known prints of the right person.
However, care must be taken not to define a print as being "sufficient for identification" if the examiner is not certain that an identification decision can be made with adequate known prints. If a case examiner continually reports suitability for "identification" purposes when impressions are really only suitable for "comparison" purposes, it is only a matter of time until a borderline impression is compared with the best known prints available and the examiner still won't feel comfortable with the evaluation of an impression that does in fact match. The result of this scenario will either be to report an inconclusive determination on a print they said was sufficient for individualization, or to report a conclusive determination they are not actually comfortable with. In short, an examiner who only reports impressions as sufficient for individualization is either setting himself or herself up for a fall, or they are missing comparisons of suitable impressions. This situation is exacerbated by the examiner not being allowed to change decisions of sufficiency at a later time. In other words, this would not be a big issue if the examiner could simply upgrade an unclaimed impression to "sufficient for identification" when compared and identified to a suspect. But some agencies believe that once a determination of sufficiency has been made, it is set in stone. This is a fallacy that must be overcome in the latent print discipline.
An impression that is sufficient for individualization purposes is always sufficient for comparison and sufficient for retention as case evidence. On the other hand, impressions that are deemed sufficient for case evidence or comparison purposes may not always be deemed sufficient for individualization purposes.
If the correct area of a latent friction ridge impression of sufficient quality and quantity for individualization is compared in the correct orientation with the correct area of sufficient quality and quantity known prints of the same area, the competent examiner who judged the prints as "sufficient" should arrive at the correct conclusion of individualization. However, sufficiency of similarity between a latent and known impression is a similar concept to sufficiency for comparison purposes: it should not be considered a static determination. For clarification, it is generally considered inappropriate for an examiner to retract a determination of identity. But if a latent print examiner who has been trained to competency by his/her agency determines early in their career that sufficient similarity does not exist between two impressions to individualize, few would argue they should never be allowed to re-assess the comparison after substantial continued education in latent print matters. Likewise, no latent print examiner should be expected to continually, case after case, year after year, make the same determination of sufficiency of agreement for individualization as another examiner, especially in cases involving problem latent prints.
Once again, those who demand agreement by all latent print examiners on every impression misunderstand the examination process of human examiners. On the other hand, an examiner who chronically determines that impressions contain insufficient agreement for individualization when other examiners identify those impressions may need to re-evaluate his/her proficiency and obtain additional latent print training. As with chronic sufficiency problems, such an examiner should not be surprised when his/her agency identifies performance as a problem and initiates measures to correct the problem. An administrative decision must be made whether to accept or not accept that level of performance. If continued operation at that level of casework performance is accepted by the agency, then the responsibility may fall upon the agency if that low level of performance results in injustice (if the examiner does not "call" an individualization of a suspect in a criminal case).
On the other hand, examiners should never feel pressure to make an identification they don't feel comfortable making. The identification decision should be completely up to the examiner, and should be made without pressure from other examiners or supervisors. The administrative decision on whether those decisions are acceptable is up to the agency. Some sort of objective measure should be explored by the agency regarding the difficulty of impressions examiners are expected to identify for that agency. In short, the agency should set the bar regarding expectations of their examiners. In addition, periodic case review should be conducted to determine whether problems exist and policy and procedure needs to be in place to deal with chronic under-performance in making identifications.
Likewise, an agency who has identified an individual who continually "pushes the envelope" and makes "dangerous identifications" may need to re-evaluate the proficiency of the other examiners in the department. Several stories have been related to the author where nobody else in the department would verify an individualization, but upon external review, verification was obtained my multiple experienced examiners and justice was served because of the correct identification in that case. If one examiner continually performs above the proficiency level of other examiners in the section, that high level of proficiency should be recognized and should not be hampered by the agency.
The author also has personal knowledge of a case where nobody else in the department would verify an individualization, so the administration recommended that the impression be externally reviewed. Upon examination by several highly experienced examiners, an exclusion was effected. Because nobody in the department would individualize or exclude the impression, the investigation continued to center on that suspect, and the error of the examiner remained undiscovered. The importance of external review in this case is emphasized because documentation was provided to the administration that the examiner was in error, and department resources were likely saved due to the subsequent re-focus of the case investigation to other suspects.
In both of the above cases, external review by experienced examiners allowed administration to determine the correct conclusion. An agency that is completely closed to the idea of seeking external verification may not allow for the correct resolution of such cases. In the first example, what would have been the determination of the agency if no external verification was allowed for the examiner who individualized an impression to a suspect but no other examiner in the agency would verify the difficult individualization? Unfortunately, the determination may have been that the examiner was in error. Nothing could have been further from the truth! Corrective action should never be taken until the correct conclusion has been determined. To prematurely consider an examiner incorrect and engage in corrective action is for the agency to invite a lawsuit from the examiner. In the lawsuit, the correct identification would surely be established and the entire section and even the department or laboratory would be embarrassed if the examiner was correct. Furthermore, if additional criminal activity was conducted by the suspect during the period of time he/she could have been incarcerated, the agency may be sued by the victims of those crimes. On the other hand, if external verification, as in the second example, concludes that the examiner is incorrect, the agency now has documentation of an incorrect conclusion and a sound basis for corrective action. If all consequences are examined, perhaps external review should not be perceived in the negative way that it currently is by some agencies.
And perhaps the reason for the negative perception of external review is because the agency will be found to have "missed" an identification. This is obviously not an ideal situation, but the more severe injustice might be if that impression was a match, but was not identified at all. If an agency truly has the desire to prevent "missed" identifications, additional training should be provided for latent print examiners, or better trained examiners should be hired or contracted to examine difficult or "problem" latents in select cases where such examinations would be of value. Given the technology of today, believe me when I say it will not be long before encrypted file transfer and secure servers are utilized for the best examiners in the country or even the world to perform precise and thorough examinations in such cases... without even leaving the comfort of their own homes.
In conclusion, the concept of latent print sufficiency is not a black and white issue. Within the work product of latent print examination, several decisions regarding sufficiency exist. An agency that employs latent print examiners should determine what type of work product they expect at each step in the process, and those definitions should be made clear to the examiners of that agency. Decisions that do not fit within the threshold of the agency must not be forced. Instead, examiners who chronically make unacceptable decisions should be dealt with through well designed policy and procedure and consistent quality assurance and quality control mechanisms designed to deal with those specific issues. It must also be remembered that a single non-conformant examiner maintaining his/her position with regards to sufficiency is not "wrong" if that is his/her position. The threshold of the examiner may be incompatible with the threshold of the agency, but their decision was correct for them. This is a difficult concept for many administrators to accept, but the opposite situation is easier to acknowledge... if an examiner is not comfortable with making a decision, and they feel forced to make the decision, they are liable to push too far on other occasions and the likelihood of error significantly increases. And it must also be remembered that just because only one examiner may effect an individualization that nobody else will verify doesn't mean they are incorrect. It is in the best interest of the agency to insure that the correct determination is known before proceeding with any type of corrective action. Many times, there may be value in having an external source make those determinations.
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