CLPEX Chat Board

Greetings all,

I have been tasked with a small research project.

I wish to ask what other agencies are doing regarding the possibility of DNA transfer when using fiberglass fingerprint brushes.

My research so far has only turned up a small amount of information. I did find the article in the Nov 2005 Journal of Forensic Science titled "Beware of the Possibility of Fingerprinting Techniqures Transferring DNA". My limited internet search did not reveal much else.

I would like to know what in-house research other agencies have performed, and what where the results. I will be working with my agency in performing our own in-house tests, and I would be more than happy to share the results with anyone interested.

Any information and/or suggestions would be appreciated.



Thank you,
Ian

Ian,
The following thread was posted on Ed German's "onin.com" website. Hopefully you will find the info of some use. I don't know if Chris Sewell did any follow-up, but you may want to try & contact him and find out. Let us all know the results of your project.
:::

Chris Sewell
Posted on Friday, May 03, 2002 - 12:58 pm:
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I do not work with latents
directly, but I supervise DNA analysis in the Washington State Patrol Tacoma Crime Laboratory. Our section has been discussing lately the possibility of DNA cross-contamination due to latent print processing. This might ocurr while dusting from one item to another, particularly if the first item was a large DNA source, such as a heavily bloodstained article, and the next was something that may have only been handled. I was wondering if anyone in the field was aware of any studies (published or not) dealing with this as a realistic possibility, and what strategies might mitigate this. Sometimes DNA samples can be taken before processing an item for prints, but it is not always an (easy, or the best) option. Thank you.

Chris Sewell
WSP Tacoma Crime Lab
csewell@wsp.wa.gov
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Ernie Hamm
Posted on Friday, May 03, 2002 - 01:56 pm:
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See the article, "A Further Study to Investigate the Effect of Fingerprint Enhancement Techniques on the DNA Analysis of Bloodstains", Roux, Gill, Sutton and Lennard, in Journal of Forensic Identification, 49:4, July/August 1999. This involves research involving powders, fuming and chemical application. In brief, no technique has a serious adverse effect under certain conditions, but some techniques should be used judiciously.

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R. L. Tavernaro
Posted on Saturday, May 04, 2002 - 08:15 pm:
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Chris,
I am a Latent Print Examiner with some experience coordinating with DNA analysts.

A few suggestions that may mitigate potential DNA cross contamination as a result of prior latent print processing:

1. Whenever possible, a face to face coordination between the latent print examiner and DNA analyst with the evidence in their collective possesion, may extend the options for DNA swabbing prior to latent print examination.

2. When powder processing is called for, consideration should be given to the use of magna-powder techniques instead of normal brush applied powder techniques. Careful application of magna-powder to each item separately in a clean environment (clean butcher paper on a benchtop may serve as a clean "enough" environment in many cases), and subsequent disposal of excess powder, should serve to minimize cross-contamination that could occur from physical contact of a brush or re-use of powder.

3. If chemical processing is required, and it is determined that the specific process that is being used (including carrier constituents when applicable) will not interfere or seriously degrade subsequent DNA examination, the labware and examination environment need to be clean before & after the latent print examination. In addition, actual chemicals used should be applied in a single item exam, throwaway context. This may be a departure from normal practice.

These are mostly just common sense laboratory practices, but perhaps you will find something worthwhile. If you research this question, I would be interested in the results.

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Kasey Wertheim
Posted on Sunday, May 05, 2002 - 10:54 pm:
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Chris,

I would like to reiterate and build upon the information that Mr. or Ms. Tavernaro has given. I also agree that the best option would be collaboration between a DNA analyst and latent print examiner before processing. I also agree with the concept of magnetic powder, as the brush does not come in contact with the evidence itself; only the powder. If one were to use traditional black powder, the brush would become contaminated, as would the reservoir containing the powder, as the brush is 're-loaded.'

I have experimented with and currently use a variety of percentage mixtures of black powder and magnetic powder. The magnetic powder makes an excellent carrier for the black powder and deposits it across the surface without contamination of a fingerprint brush. I use a mixture of approximately 50% black and magnetic, but I have mixtures with less black powder all the way down to pure magnetic powder. Different percentages are ideal for different surfaces.

By utilizing percentage mixtures, you still get the effect of black powder without the cost involved in disposing of contaminated brushes. Of course, you cannot "clean" the print up using a camel hair brush or feather duster because of contamination, but a blast of compressed air from a distance (start out farther away and work inward) does nicely. And I'm sure you know not to blow across the print to remove excess powder, or YOU may end up on the suspect list!

Hope this info helps, and good luck!

-Kasey Wertheim
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Regards, RLT

A few years ago a study on this topic was carried out by the ESR in New Zealand in conjunction with the NZ Police SOCOs in Christchurch. I may be able to find out more if you are interested.

About the use of magnetic powder.

Will that not pick up DNA as well? Especially if you return the powder to the pot after use?

Sorry I am a beginner at this and it would be very interesting to know.

As I was researching for my final year project I came across these articles. I don't know whether you have it or not. If you want a copy email me
EmmaClemson@blueyonder.co.uk and I will forward it to you.

"Beware of the Possibility of Fingerprinting
Techniques Transferring DNA

Roland A. H. van Oorschot,1 Ph.D.; Sally Treadwell,1,2 B.Sc. (Hons.); James Beaurepaire,1,2 B.Sc. (Hons.);
Nicole L. Holding1,2 B.Sc. (Hons.); and Robert J. Mitchell,2 Ph.D.

J Forensic Sci, Nov. 2005, Vol. 50, No. 6"
Paper ID JFS2004430

"Experiments on the DNA contamination risk via
latent fingerprint brushes

C. Proff *, C. Schmitt, P.M. Schneider, G. Foerster, M.A. Rothschild

International Congress Series 1288 (2006) 601– 603"

Hope they help.

Neville,

I am definitely interested....

Any information and/or a contact person would be appreciated.


Thank you,
Ian

Of course you don't return the powder back to the container after using the magnetic brush on an item. You thrown it away and get a fresh supply for the next item, and so on. It's a lot cheaper thrown away a little bit of powder than get a new brush each time!

the Christchurch Team are looking for the research paper and will get back to me.

Check out this site http://www.esr.cri.nz/competencies/forensicscience/dna/
there is a email link on the right side.
The Paper I refered to is called Evaluation of fingerprint powder enhanced impressions for subsequent DNA testing July 2004 written by Jo Bright, Bjorn Sutherland and Steve Cordiner.

Unfortunately I do not feel I can forward it to you as it states clearly that it is prepared for the benefit and information of the New Zealand Police.

Howdy,
The information is limited regarding FP residue and DNA. I found a couple of good sites, one being Officer.com July '05 article by Rebecca Knable about low copy DNA used in the UK. Extraction of DNA from FP residue is very new thought. However, it's wise to be prepared for the future. Cold cases are being solved today with evidence packaged long before the introduction of DNA as a law enforcement tool. It is important to be aware of the possibility of DNA when processing any evidence. I would especially look for DNA on the adhesive side of tape, before processing for prints.
A Magnetic Applicator using a light touch will afford the least chance at cross contamination of DNA. The TEX Magnetic Applicator weighs slightly over 1 oz. and has a removable outer cover which can be cleaned or replaced between cases. Do not replace powder back into the jar!

J.R.

I posed this question to Professor Kobilinski, renowned forensic DNA Scientist at John Jay College. His belief is that although the potential for cross contamination is real, the precentages of material should be explainable. His view is that as few as 16 epidemial cells can yield as useable profile under current replication techniques. He also theorized that the brush should make such light contact with the latent print surface, that any biological material present should overwhelm any contamination.

Understanding that anything can contaminate a sample, I have been instructing within my agency: (1) Identify the area for finger recovery with oblique lighting. (2) Identify a specific area that may not yield a ridge structure or an identifiable ridge flow. (3) Collect a swab from this immediate area (2) for potential DNA. (4) Collect a swab from the surface near by, from the target area. (5) Then process the target area for the latent fingerprint.

I also advise that DNA may not be unique to the individual as the latent fingerprint, in the case of paternal twins, triplets, etc., or if another individual had come into contact with the hand leaving the latent print, the DNA may not be specific to the contributor of the latent image.

I have not performed any research on this practice, but working in small departments, with limited budgets, it would be cost prohibitive, time consuming, to use one Zepher brush, one clean sample of fingerprint powder, dispose of the magnetic powder and clean the magnetic wand for every new fingerprint image.

Again, not scientific, just idea!

Howdy,

Cold case investigators are testing old evidence for DNA, even though it was processed for latent prints. I have no data on their success rate, but I don't think they would waste their time trying if it was impossible. Perhaps the situation is not either/or, but rather both. Maybe we can dust for prints and also swab for DNA.
Reflect for a moment, all of the times in the past you have re-dusted a print and was able to obtain a second lift. This is because the residue and the DNA remained on the surface after the lifting process. I don't believe the small amount of fingerprint powder on the swab will prevent DNA testing. But if it does, can we just include a known sample of the powder for elimination purposes?

DNA transfer with a brush is possible, even with magnetic powder .A few examples of studies:
http://www3.interscience.wiley.com/cgi- ... 1&SRETRY=0
http://www.promega.com/geneticidproc/us ... murray.pdf

With super-glue, there is no brush at all and it is perfectly possible to obtain a DNA-profile from a print, after CA.
So our policy was: first CA, documentation of the useful print ; is necessary DNA can be done on the smears. This has the advantage the DNA-lab gets a good indication where they have to take there swabs.

Bert VAN DIJCK
Federal Police Antwerp - Belgium (rtd)