UPDATES ON CLPEX.com

No major updates on the website this week.

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we completed a series on U.S. patents related to latent print examination.

we view a few noteworthy news related fingerprint items.

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Fingerprint Identification: The Role of Research in Fortifying the Forensic Sciences

Thursday, May 10 at 2:00 p.m. EDT
Free online event. Registration required.

Fingerprint technology is improving rapidly. It is also more cost effective than DNA but is vastly underutilized.

This event, sponsored by the Government Innovators Network and the National Institute of Justice, assembles an expert panel to discuss the following topics:

* What are the barriers to maximizing the usefulness of fingerprints?

* What does it take to be a good fingerprint analyst?

* How do we better share AFIS (automated fingerprint information system)
technology?

* What are the emerging practical techniques and improvements?

View the panelists and register
http://www.ojp.usdoj.gov/nij/redirects/redirect04-25-2007.htm

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The FBI Criminal Justice Information Services (CJIS) Division will be hosting the next Tenprint and Criminal History Record Training "Chat" style Training Session via Law Enforcement Online (LEO) on Wednesday, May 9, 2007, at 2 p.m. (EST).  The topic will be "The Importance of Tenprint Cards."

This session will be moderated by the Identification and Investigative Services Section's (IISS) Training and Records Tesimony Team (TRTT).  For any questions regarding the content of the Chat Session, please contact Ms. Nikki Hermosilla of the TRTT at (304) 625-3541.  For help setting up the Chat or connecting to the Session, please contact the LEO Help Desk at 888-334-4536.

Please disseminate this email to anyone you believe may benefit from this information/training.

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New Ultrasound Fingerprint Identification System Suggested

Science Daily — Diagnostic 3D ultrasound of fingers could be used for biometric identification based on matching paired images using internal fingerprint structures that would be difficult to fake, offering the possibility of a unique automated fingerprint identification system, according to a new study by researchers from the University of Michigan in Ann Arbor.

For the study, 3D images were collected of the fingers of 20 volunteers. A group of four readers, including two musculoskeletal radiologists, then attempted to match the pairs based on anatomic and physiological features of the human finger. Radiologists matching the image pairs were 100% successful, and the average success of all four readers was 96%.

"The purpose of the study was to evaluate whether the use of internal finger structure as imaged using ultrasound could act as a supplement to standard methods of biometric identification. Also, this study provides a way of assessing physiologic and cardiovascular status, for example, whether the person is alive or not, which is not known from just their external fingerprints. There is a wide range of applications for an inexpensive ultrasonic fingerprint reader, including widespread use in cell phones," according to Ganesh Narayanasamy, PhD candidate in Applied Physics and lead author of the study.

Besides its many possible biometric identification uses, the findings also have a medical application, say the authors. "This could become a method of patient identification and even continuous physiologic monitoring. The techniques should become useful for other types of musculoskeletal ultrasound and for monitoring of arthritis treatments," said Dr. Narayanasamy.

The full results of the study will be presented on Monday, May 7 during the American Roentgen Ray Society Annual Meeting in Orlando, FL.

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Pointing the finger
[April 23, 2007]
Article by Steve Down

Law enforcement officers have been supported by forensic science for decades and new techniques appear with heartening regularity to help the fight against crime. Advances in the analysis of inks help to trap forgers and counterfeiters, improved image enhancement techniques provide better details from footprints and impressions, and skilled computer technicians can extract "lost" information from personal computers.

But one technique that has completely revolutionised forensic science is DNA testing, due to its remarkable ability to place one person at a crime scene with absolute certainty. This is guaranteed by the practically unique nature of an individual's DNA compared with all others. Before DNA technology was developed, the closest tool that forensic technicians had was fingerprint analysis. Fingerprints, too, are unique, but they have a distinct disadvantage compared with DNA.

Fingerprints can degrade with time, so that some visualisation methods are less effective than with fresh prints. Since many crimes go undetected for some time, or evidence is recovered at a later date, the degradation of prints can become an important factor. The characteristic ridge pattern may not reproduced with sufficient accuracy for a positive identification.

Fingerprints consist of a mixture of substances released from the skin glands, including lipids, amino acids, salts and water, complemented in some cases by environmental components. It is known that lipids oxidise fairly readily and chemists from the Department of Forensic Science and Drug Monitoring, King's College London have previously shown that one major lipid component, squalene, is depleted quite rapidly after a print has been deposited.

Now, these chemists, led by Sue Jickells, realised that the chemical changes that reduce the amounts of squalene would form new products that are potential candidates for a new type of fingerprint visualisation agent. If the products could be identified and a visualisation agent developed, it might be possible to estimate the time elapsed since a fingerprint was laid down.

In initial studies, the researchers oxidised squalene in solution using the photooxidising agent Rose Bengal. The reaction mixture was analysed by semi-preparative HPLC with UV detection, which revealed the presence of several products. Subsequent analysis by TLC and mass spectrometry with electrospray ionisation (ESI) and atmospheric pressure chemical ionisation (APCI) confirmed the formation of squalene oxide and the hydroperoxides from squalene mono- to penta-hydroperoxide.

Squalene is a multi-branched hydrocarbon (2,6,10,15,19,23-hexamethyltetracosane) so there are several potential sites at which oxidation can occur to give these multiply substituted products.

For further studies, APCI MS was preferred as it gave more consistent formation of sodium and potassium adducts and better ionisation of squalene itself. The team went on to develop an HPLC/MS method with APCI for analysing the oxidation of squalene in solution and in latent fingerprints, that is, prints invisible to the naked eye.

In the absence of Rose Bengal, squalene in solution was still oxidised quickly, with only 3% remaining after 2 days in a 24-h light room and less than 1% left after 15 days. The fact that squalene epoxide and mono-hydroperoxide were also observed in the starting solution confirmed the ready oxidation of squalene. After 20 days, even though squalene was no longer detectable, the higher hydroperoxides were still present. If this behaviour was reproduced in real fingerprints, then the hydroperoxides represent targets for fingerprint detection.

Fingerprints from a volunteer were deposited on a glass coverslip after the subject ran the fingertips across the face and through the hair. They were stored in a light room and sampled for up to 7 days. The lipids were extracted with acetonitrile and the oxidation products analysed by HPLC/MS.

Oxidation was again rapid, with squalene epoxide and mono-hydroperoxide increasing after one day, levelling off after 1-5 days and becoming almost undetectable after 7 days. Oxidation was faster in real prints than in the test solutions and Jickells attributed this to the starting concentrations of squalene which were around 100-fold higher in solution than in prints. The lower levels of squalene in the prints were depleted quicker, after which no oxidation products could be formed.

The higher hydroperoxides were not measured in the prints, but comparison with the solution studies indicates that they would be formed and might persist after the squalene had all been lost.

The results suggest that squalene hydroperoxides should be investigated further as targets for new fingerprint visualisation reagents. They might prove useful for older prints, especially if it is found that the higher hydroperoxides have lifetimes in the region of 20 days or more, as in the solutions.

Apparently, it is often the case that a suspect is placed at a crime scene by fingerprint detection but claims to have been there before the criminal act took place. If the kinetics of squalene oxidation were taken into account, it might also be possible to age the fingerprints and prove or disprove a suspect's claims.

Related links:

Department of Forensic Science and Drug Monitoring, King's College London
http://www.kcl.ac.uk/schools/biohealth/depts/forensic/

Analytical Chemistry 2007, 79, 2650-2657: "Identification of oxidation products of squalene in solution and in latent fingerprints by ESI-MS and LC/APCI-MS"
http://dx.doi.org/10.1021/ac0623944

Article by Steve Down

The views represented in this article are solely those of the author and do not necessarily represent those of John Wiley and Sons, Ltd.

Link to full article:
http://www.separationsnow.com/coi/cda/detail.cda?id=16161&type=Feature&chId=4&page=1