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Monday, November 5, 2001

Welcome to the thirteenth "Detail," a weekly e-mail newsletter that greets latent print examiners around the globe every Monday morning. The purpose of the Detail is to help keep you informed of the current state of affairs in the latent print community, to provide an avenue to circulate original fingerprint-related articles, and to announce important events as they happen in our field.

BREAKING NEWz you can UzE...

Autographed copies of Ashbaugh's QQFRSA (signature and his thumb print on the title page) now available at the CLPEX.com bookstore!    Order your copy while they last!

It's BidNow Week!!  This month's CLPEX.com Ebay item is a neat old inked print kit in a maroon leather-like case.  It was manufactured by Ace Fingerprint Equipment Laboratory in Chicago, and consists of a fingerprint pad and two bottles (appear unopened) of Ace Fingerprint Ink.  For pics and more details, check it out on Ebay and  Bid Now!


This week Steve Ostrowski shares his insight from a recent project on Simultaneous Impressions.  I will let him introduce the project and explain the outcome.  This Detail is more lengthy than most, but it is well worth the read, and could spark some valuable discussion on the board.  Enjoy!


Simultaneous Impressions:  Revisiting The Controversy

The New Hampshire State Police Forensic Laboratory takes pride in its conservative approach to reporting.  In the history of our laboratory, never has there been a misidentification reported on.  Since the mid 1990’s, the fingerprint examiners in the lab were not authorized to identify simultaneous impressions on accumulative weight.  This decision was based upon the experience level within the section as well as the results of the 1996 CTS proficiency test in which two simultaneous impressions were depicted.  We set out to gather information for a debate that would revisit the question of whether we would be authorized to identify individuals based on the accumulative weight of a simultaneous impression.

 Our strategy was to present our knowledge of the science of fingerprints and supplement that with our findings in literature.  We would then present the results of the survey illustrating how other agencies are addressing the issue. We also formed a correlation to similar tasks in other disciplines within the identification section.  An example of this is the determination that the heel portion and the toe portion of a two-dimensional boot impression can be shown to be made simultaneously and thus be considered one impression.  The detail in both portions of that impression can then be used for identification purposes.  We also would note that fact that when using the accumulative weight of several neighboring impressions, the ridge detail must be in the same corresponding areas, be in the same sequence and have the same individual uniqueness in both the latent and the inked impressions.  Ridge detail simply being present was not acceptable.  We also prepared a statement that the integrity of the laboratory is important to us, but not as important as our own careers.  A misidentification would have greater ramifications on us as individual examiners compared to that of the agency as a whole.  We were not about to start calling everything simultaneous impressions just because we could.  We were ready to debate.

 During our research, we quickly learned that there is not much information written specifically on the subject of simultaneous friction ridge skin impressions.  The Journal for Forensic Identification and the internet yielded little information for our intentions.  We did find that ‘simultaneous impressions’ were referred to in the following:  Guidelines for Training to Competency for Latent Print Examiners by the Scientific Working Group on Friction Ridge Analysis, Study and Technology (SWGFAST) (taken from web site); Introduction to Fingerprint Comparison by Gary W. Jones  (we only viewed the table of contents on the internet); Latent Print Examiner Training Program by the Joint Committee on Fingerprint Training and Curriculum of the IAI, 1990; and an article entitled Technical Working Group on Friction Ridge Analysis, Study and Technology (TWGFAST) Proposed Guidelines, Journal of Forensic Identification, Vol. 47, No. 4, 1997.

 Our best information was found in two texts.  David R. Ashbaugh’s Quantitative-Qualitative Friction Ridge Analysis:  An Introduction to Basic and Advanced Ridgeology, CRC Press , 1999, pp. 129-36 and James F. Cowger’s Friction Ridge Skin: Comparison and Identification of Fingerprints, Elsevier Science Publishing, 1983, pp. 154-8.  The aforementioned pages were found to be the backbone for our endeavor.

We studied the results of the 1996 CTS test.  That year, 191 sets of results were returned to CTS.  Results showed that 108 agencies identified both impressions in question (#3 RM, #4 RR) correctly while 59 agencies identified only the one impression (#4 RR) correctly.  Were these prints simultaneous?  Yes, because they were left at the same time.  No, because one of them was able to stand alone.  In my opinion, each of the impressions was identifiable on its own.  It is impossible to know what each examiner was thinking at the time they were analyzing those impressions.  Factors which affect the reporting of these impressions are:  a) examiners work under the regulations of their agency, sometimes despite their personal feelings and b) multiple examiners in a unit may have their answers reviewed and consolidated into one answer reported on from that particular agency.  We will never know the whole story.

 We decided to conduct a survey to gather information on who was calling simultaneous impressions and under what criteria.  The survey consisted of five questions and was dispersed via email and telephone conversations to a variety of examiners across the nation.  Of the 18 responses, there was representation from local, state and federal latent print examiners from 13 US states and Washington D.C.  The five questions asked and a brief summary of the corresponding results were:


1.      What is your agency’s policy concerning the identification of simultaneous            impressions based on the accumulative weight of the impressions? (i.e., does at least one have to “stand alone”)

All but one response stated that agencies have no policy on simultaneous impressions.  One agency requires each impression to stand alone.


2.      Is there anything in writing specifically outlining your agency’s SOP concerning the aforementioned or is it more of an unwritten rule?

All responses indicated that there is nothing in writing concerning simultaneous impressions.  SWGFAST is currently dealing with this same question.


3.      In your agency, is it the discretion of each examiner as to their personal criteria for calling an ident on a simultaneous impression?  In other words, do some examiners call it when at least one of the prints can stand alone while others call it when none would be able to stand alone?

The general consensus throughout all of the responses was that ultimately it comes down to each examiner.  One agency was reported to reassign cases to other examiners who have certainty to call a simultaneous impression.


4.      During your analysis of a simultaneous latent, how many of the prints do you personally require to “stand alone” to determine if it is suitable for identification? (none, one, all)

Approximately 44% of those asked reported requiring one latent to stand alone to call simultaneous impressions.  One agency dictates that all impressions must stand alone.


5.      When you have come to the conclusion of identification on a 3-finger simultaneous impression, do you consider that 3 idents or just 1?  How do you report on it?

Of those who call simultaneous impressions, approximately 71% report identifications as one identification.  The reoccurring thought was when more than one latent impression is used accumulatively and in sequence for an identification, the totality of that image should be reported on.

 In the end, we had won our case with little opposition.  It was noted that this is an advanced technique that should be utilized with the utmost scrutiny.  It was decided that there would be a reference to simultaneous impressions written in the New Hampshire State Police Forensic Laboratory Identification Section Standard Operating Procedure.  In our General Practices SOP, it will be noted that simultaneous impressions are to be treated as a single impression.  They will be compared using the accumulative weight of the friction ridge detail in sequence for all of the impressions.  They will be reported on as, “…the latent impression of value developed on exhibit A was identified as the fingerprint impressions of John Q. Doe (dob 01-02-99).”

 During our investigation, we discovered early on that simultaneous impressions are somewhat of a mysterious concept.  They are sometimes referred to as cluster impressions, adjacent impressions or a grouping.  They have different meanings to different people even within the same agency.  It is quite evident that not everyone is handling these types of impressions in the same manner.  Simultaneous is defined by Merriam-Webster’s dictionary as “existing or occurring at the same time.”  However, there seems to be varying interpretations of how simultaneous impressions are used to effect identifications. 

 We are taught that one impression is all that is needed to identify an individual, whether it be a single latent fingerprint, palm print or simultaneous impression.  I believe there to be two connotations of the term ‘simultaneous impressions’ when referring to latent work.  The first is the physical presence of impressions of neighboring fingers made with one touch.  These simultaneous impressions can be comprised of two, three, four or five fingerprint impressions.  They can be on different planes (e.g. two opposing sides of a window).  The quantity and quality of ridge detail in these impressions can vary greatly.  This determination of ‘simultaneous’ assists us with orientation and limits our search.  Do we have to identify each of these impressions if they have sufficient detail?  What if only some of them are sufficient?  Do you have to identify all the fingerprint impressions in an latent of a full palm with all 5 fingers?  If one of the prints has sufficient quantity and quality of ridge detail to be identified and the remaining prints do not, is it necessary to define these impressions as ‘simultaneous’?  What is the advantage for a latent print examiner to call these impressions simultaneous?

 The second connotation deals with Ashbaugh’s ACE-V methodology of latent print identification.  On occasion, simultaneous impressions may not contain a single impression which is able to stand alone.  Since simultaneous impressions are made with one touch, they could be considered a single impression.  They can be compared using the accumulative weight of friction ridge detail in sequence for the entire grouping.  This connotation expands on the first in a way that causes some examiners to feel uncomfortable or to simply disagree.  On the contrary, other examiners believe that after the identification of an impression that stands alone, it is a waste of time to subsequently try to identify the remaining impressions (sufficient or insufficient) in the grouping when the donor has already been identified.

 It was apparent to us that people use the connotations interchangeably.  Some examiners say they have simultaneous impressions and would report 1 ident.  Some examiners say they have simultaneous impressions and would report 3 idents.  Some feel the need to identify everything they can while others just want to identify an individual.  Who is right?  What is the definition of ‘simultaneous impressions’ and how should we use them?

 James Cowger says that, “even if the individual prints are inadequate for a conclusive determination of identity, that the donor can be identified based upon a comparison of the entire group.”  Before that can happen, a complete scientific analysis of the latent impressions is needed before coming to the conclusion that a grouping of latent impressions are indeed “simultaneous.”  Anatomical features, indications of normal handling, consistency of development medium, deposition characteristics including various directions of distortion are just some of the indicators leading to a decision of simultaneous impressions.  Pat A. Wertheim teaches 21 different aspects of latent impressions to consider during analysis.  Once these aspects have been properly noted, the results could lead to the conclusion that a grouping of latent impressions is indeed simultaneous.

 In a grouping of two or more impressions where only one of the prints is independently identifiable, all that is required to identify an individual is that one print.  The other neighboring impression(s) would no longer be considered for identification purposes because they are independently of no value for comparison purposes. 

 The only time an impression of no value for comparison purposes could be kept and compared is when it is grouped with an additional impression(s) of no value for comparison purposes.  The friction ridge detail of the impressions in the group would be compared in sequence, the accumulative weight of their uniqueness would be evaluated, and individualization of the donor could then occur.

 David Ashbaugh said it best when he wrote, the “purpose of friction ridge comparison is personal identification of the donor and not the identification of a specific finger or palm print.”  Despite all that has been said to this point, it will always boil down to the comfort level of the case examiner and the verifier(s).

 Special thanks goes out to all who responded to our survey, members of the NHSP Forensic Lab Identification Section and our lab director for all of the hard work in illustrating that science and biological uniqueness still exists in simultaneous impressions at our laboratory.

 Stephen H. Ostrowski
New Hampshire State Police Forensic Laboratory


Thank you, Steve, for sharing your insight with us!

Do you feel strongly for or against the use of simultaneous impressions for individualization?  Express your viewpoints at the discussion forum and let's all learn together!

Next week, Andy Kearns brings the issue of production standards for latent print examiners to the table.  Do you think examiners should be required to work a minimum number of cases every month?  Stay tuned, do your homework, and be prepared to bring your thoughts to the Discussion Forum on this issue NEXT week!


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