UPDATES ON CLPEX.com

Updated the Fingerprint Interest Group (FIG) page with FIG #53; movement, doubling; submitted by Bonnie Manno.  You can send your example of unique distortion to Charlie Parker: Charles.Parker@ci.austin.tx.us.  For discussion, visit the CLPEX.com forum FIG thread.

Updated the forum Keeping Examiners Prepared for Testimony (KEPT) thread with KEPT #28; Research Studies - Lockheed Martin 50K X 50K study, submitted by Michelle Triplett.  You can send your questions on courtroom topics to Michelle Triplett: Michele.Triplett@kingcounty.gov

Updated the Detail Archives
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we reviewed the NIJ funded latent print training program sponsored by the National Forensic Science Training Center (NFSTC).

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Origin of the Powder Rubbing Technique
Original Article in FP&ID Magazine, by Michael R. Grimm, CLPE and Richard A. Taylor, CLPE; with posting and commentary by Ed German, onin.com Webservant
http://onin.com/fp/powder_rubbing_technique.html

In the decades since the post-cyanoacrylate (super glue) "powder rubbing" process was published, many agencies have adopted it as the last step in examining any nonporous (glass, metal, plastic, etc.) surface. Because cyanoacrylate polymerization creates a relatively strong three-dimensional structure when latent prints are developed, powder can be rubbed over such cyano-processed prints (as a last step in the processing sequence). The powder rubbing process can create contrast that enables photography and identification of previously undetected friction ridge impressions.

The following excerpt was extracted from "Super Glue Sticks It to the Bad Guys", published in Identification News, Vol. 34, No. 2, March 1984, pages 7-11, by Michael R. Grimm, CLPE and Richard A. Taylor, CLPE, both employed by the Virginia State Crime Laboratory in Roanoke, Virginia, USA.

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... Within the past month a discovery was made involving the use of super glue to process plastic bags from two drug cases and a petit larceny of a black powder pistol kit. In the first case sixteen baggies were processed in the conventional manner - with only one showing a little ridge detail of no value for identification. While holding the bag up to the light for better viewing it slipped out of the examiner's hand, which was protected by the use of rubber surgeons gloves. Upon examination of the area that was under the thumb and forefinger where the bag was held, it was noted that ridge detail had “appeared,” white ridges with a very light brown colored background! Further deliberate ‘ rubbing ‘ of the bag with the rubber surgeons gloves produced two fingerprints of value for identification. Subsequent treatment of the remaining fifteen bags resulted in two more fingerprints of value, two of which were later identified as the fingerprints of one of the suspects. Similar treatment of the cellophane wrapped pistol kit produced a palm impression of extreme clarity showing even the fine pore structure of the ridges. The latest case entailed the processing of eight bags of cocaine. Conventional methods produced no discernible ridge detail. However, use of the "rubbing technique" supplied the examiner with two fingerprints later identified as those of one of the suspects.

The “rubbing” technique appears to change the black powdered surface to a shade of light to medium brown with the ridge detail appearing in white. Very vigorous rubbing seems to enhance the ridge detail rather than delete it as you might expect....

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The color of the friction ridge detail developed with this process depends on several factors, including the following:

- The color of powder used;
- The presence of contaminants on the surface;
- Whether the friction ridge impression was deposited from the finger/palm, or was caused by the finger/palm removing (lifting away) part of a contaminate coating already present on the surface.

The basic concept is that the powder is rubbed on the relatively smooth surface bearing hard, three-dimensional (super glue-developed) ridges and furrows of cyanoacrylate polymer, causing contrast by filling furrows and accumulating powder on each side of the three dimensional friction ridge detail.

Many latent print examiners have used this technique to reveal impressions that were previously invisible by cyanyo-fuming followed with dye-stains, laser examination and "normal dusting" with fingerprint powders. Sometimes the failure of detection through dye staining and laser (or alternate light sources) exam may be due to background/substrate luminescence that quenches (competes with) the faint glowing of weak (minute deposit) friction ridge impressions. Sometimes the lack of detection through normal dusting after cyano-fuming may be due to the absence of sufficiently "sticky" friction ridge deposits.

This technique is simple, inexpensive, and risks nothing when all conventional techniques have already been exhausted without developing identifiable latent prints.

Nothing works to successfully develop latent prints on all nonporous surfaces and the powder rubbing technique will definitely not produce successful results each time it is used. However, consistent use as a last-step procedure on nonporous surfaces will produce enough successful instances to convince examiners to always consider it when all other steps have failed.

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KEPT - Keeping Examiners Prepared for Testimony - #27
Methodology Error Rate - Theoretical vs. Actual
by Michele Triplett, King County Sheriff's Office

Disclaimer:  The intent of this is to provide thought provoking discussion.  No claims of accuracy exist. 

Disclaimer:  The intent of this is to provide thought provoking discussion.  No claims of accuracy exist. 

Question – The FBI - Lockheed Martin 50k x 50k Study:

Any question regarding the FBI - Lockheed Martin 50k x 50k Study.

Possible Answers:

a)      This was a research study done in 1999 to show support for the theory of biological uniqueness of fingerprints.

b)      This was a study that showed the probability of the same configuration of minutia occurring in two fully rolled prints is 1 in 10 to the 97^th power.  The probability of a latent print having the same minutia as another rolled impression is 1 in 10 to the 27^th power.

c)      This was a study done in 1999 by the FBI and Lockheed Martin.  This study has never been published or peer reviewed to show if the study or the results are scientifically sound.  Until this is done it would be improper for me to testify to this study.

Discussion:

How you chose to testify is your choice but even if you have in-depth information regarding this study, it may not be scientifically valid since it hasn’t been peer reviewed.  Giving the jury information you know isn’t supported, isn’t educating the jury but it’s a sign that you’re trying to convince the jury of your view.  This is a sign that an expert witness isn’t independent or objective in their views and some people may consider this to be an inappropriate action.

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Have a GREAT week!