CLPEX Chat Board

“Yes, I know that's not true, but as appellate counsel all I can do is drop a footnote about sloppy crime scene work -- trial counsel didn't catch it at the time.) Please, publish this stuff in hopes that folks will take prints of the once-wet stuff!”

I will contact my colleagues who assisted in the experimentation as well as the CSI (a former student) on the actual case recovery to see if they are interested in in writing an article. Many times why this hasn’t been done is that it is commonly thought that this is or should be common knowledge to those who are in the field. I am not referring to a specific experiment but what CSI and firearms personnel should take into consideration.

If it is not in the main stream, many say it won't work, yet when they are asked have you tried it, there is usually a long pause and then the answer no they hadn’t. Before you say no, try it and if it doesn’t work try it again as you may have done something wrong. (As an example the citation of the person who did not process the vehicle because it rained)

I was told that being inquisitive and having a good sense of deductive logic and cognitive ability makes a good CSI.

I'm suspecting that the idea that water destroys prints may have come up at a CLE or training class in CT. I had another examiner (different agency from the first fellow) in a homicide case testify that had the co-defendant thrown the murder weapon into a local pond, that would destroy any prints. (The police had recovered the weapon before it was dumped in the pond, but knew that the co-defendants were planning to dump it.)

In that case it was a very minor point, but it reminded me that there seems to be a belief in at least two CT departments that water destroys latents and it isn't worth trying on once-wet surfaces.

(Anyone from CT willing to comment on this?)

That was odd -- the board logged me in as G.Frog on that last post!

I have just logged a help desk event, so we'll see what the issue was. Thanks for the quick notification.
-Kasey

Hello! As someone who has never tried to develop fingerprints from firearms, I can only explain some of the basic principles and techniques that are indicated in the literature. I hope this helps!

Water will wash away the water-soluble components of the fingerprint, but leave behind the lipid-soluble, or greasy components of the fingerprint.

Therefore, it is useless to try to develop fingerprints using reagents or techniques that are designed to target water-soluble components in the fingerprint, such as CA fuming.

So you need to try something like direct powdering (although this is likely to smudge) or perhaps SPR (see reference below which performs some nice testing and lists advantages and disadvantages of the technique).

Onstwedder III, J. and Gamboe Jr., T. E. (1989) Small particle reagent: developing latent prints on water-soaked firearms and effect on firearms analysis Journal of Forensic Sciences, 34, 321-327.

Kind regards,
Shaheen

Some fact and some myth. What are the citations in literature that you refer to?

Dear G. Frog,

"Water will wash away the water-soluble components of the fingerprint, but leave behind the lipid-soluble, or greasy components of the fingerprint."

Champod, C., Lennard, C., Margot, P. and Stoilovic, M. (2004) Fingerprints and Other Ridge Skin Impressions., CRC Press LLC. pp110

"Therefore, it is useless to try to develop fingerprints using reagents or techniques that are designed to target water-soluble components in the fingerprint, such as CA fuming."

I am currently writing up this paper from my own research. CA sticks to water and material that is hygroscopic (these are all water-soluble). I also presented these findings at the recent IAFS meeting.

Please expand on which sections were myth, with citations, as I would love to see experimentation that proves these dicta wrong.

Kind regards,
Shaheen

I just have to add my opinion here as to weapons being submerged in salt water, I know its a little off point. My department recieved over 300 weapons that were submerged in salt water for less than 24 hours and then recovered after Hurricane Katrina. In fact, most were recovered within two days of the storms aftermath. With exception of three stainless steel pistols, all of them rusted and were extremely pitted and useless. the Three stainless steel pistols were also rendered useless as the steel ineer parts also rusted. To render these weapons safe they had to be severly beat and pryed on. The barrels of most of these weapons were trashed and I can in no way see them ever to have a bullet travel down their exsistance ever again (so sad).
Just my observation.

I respect your observations. I personally find it hard to believe such a blanket statement. Oxidation takes time and pitting even more so. Were the lands and grooves pitted? How long were the weapons under water (you indicate 24 hours) and how long where they exposed to air after their recovery from water (you indicate 2 days)? Were they in mass and stored at a facility?

I am aware that there were laboratories or evidence rooms in the tri state area submerged under water after Katrina.

Afetr receiving the weapons what precautions were taken to avoid the oxidation process? Where were they taken to?

"Therefore, it is useless to try to develop fingerprints using reagents or techniques that are designed to target water-soluble components in the fingerprint, such as CA fuming."

Let me make a suggestion regarding your research.

Obtain a series of glass slides

Lipids
Water
Isotonic Saline Solution
Sebaceous material - sterile swabs rubbed over the facial area and neck.

Sterile swabs

Utilizing the sterile swabs saturate one each with, lipids, water. Saline solution and sebaceous material. Using a new slide for each application mark an X on the slide, set aside for controlled period of time and then super glue fume at Use a hygrometer to check the temperature and humidity. The best of both worlds is to have 80% humidity and 80F temperature.

Try different processing techniques with superglue. You will need a set of separate slides for each.

Chemical accelerator.
Heat
Evaporation.


What slides develop the X? Please let us know your results. Others who are curious may want to do the same thing.

To further substantiate and your edicifation immerse a set of slides underwater. Use a separate set of slides and place them under water for a period of time and then remove them, set aside and allow them to dry before processing with superglue. Don’t believe all that you read, try it.

Hi Guest,

I have a number of points to bring up:

1) When you say "lipids", what are we talking about here?

2) Could you please summarise the results of your tests (ie, which reacts when you perform the experiment?)

3) It's all very well to make an "X" visible with CA, but when a fingerprint is involved, I have not been able to maintain good resolution of ridges and sulci because the print has smudged after washing with water. SO rather than nothing polymerising, everything polymerises and you just get a smudgy blob.

4) This difference could also be due to the slides used, if you are finding that you still get prints, which is another point - have you tried your experiment specifically on firearms? I have found that the support really does affect the results of fingerprint development.

Cheers,
Shaheen

lipids as used in DNA testing.

Yes in actual cases and in experimentation and prints were recovered.

As most natural fingerpint residue contains oil, prints remain on substrates which have been immersed in water. Re read Champod as you previously provided citation.

Instead of resisting why not try the experiment, just try it. An attitude of it can't be done will result in exactly that it can't be done because you haven't tried it. Skeptisism is fine but a skeptic is a differnt animal.

You can lead a horse to water but you can't make him drink!

If you want to short cut all of this then try wipping the ridge detail of two fingers across your brow and then apply the contaminated prints to the inside of a water glass. Fill the glass with water. Let the glass of water covering the prints stand overnight and then empty the water. Allow to air dry. What are your results? Then CA the glass and what are the results.

Try it with water as the contaminate on the ridge detail and repeat. I think you will find that the prints deposited with water will not devlop even with out filling the glass with water if there is not a cross contaminate on the ridge detail.

You shouldnt CA a wet surface let it air dry. If there haze or light blooming masking the print, rub it out, it will not destroy the developed or fixed print unless you rub too hard.

We are not discussing washing with water but immersion. A gun, glass thown into static water such as a pond, lake or swimming pool. Keep in mind that the Ph factor of the body of water plays an important part in the successful develoment of prints with DNA in these situations. Also the colder or cooler the water the better the results. Remember after removal from water let the substrate air dry before CA application

The world is flat?

TA TA for now. Good hunting

" It's all very well to make an "X" visible with CA, but when a fingerprint is involved, I have not been able to maintain good resolution of ridges and sulci because the print has smudged after washing with water. SO rather than nothing polymerising, everything polymerises and you just get a smudgy blob."

Opps I forgot, we are not talking about quality of the latent print in this experiment but rather to either substanciate or refute the residues which CA reacts with.

From what I am interpreting there may be a tendancy for the over development of print residue, unless you are basing your comments on hearsay or publications.

Can a horse fly?

Cheers

Ok, you know what? I'm sick of guest's derisive comments.

I could happily discuss my experimentation here but I prefer to continue this conversation offline with more mature and interested parties, since it is of no benefit to myself to continue in this fashion. I would like to juxtapose some of the different theories about how CA is behaving and not just observe but to attempt to explain the chemistry behind it, as well as ascertain why some results are not robust (particularly when performed overseas). I would love to hear from others who can contribute experimental results as well as debate the meaning of the results collectively.

You can email me at shaheen.aumeer@uts.edu.au

Please do not bother if you do not posess the spirit of collaboration and co-operation. I don't have time to talk to an #$$@.

my my my your description of others certainly appears to fit you to a T, perhaps if you werent so narrow minded and focused you may learn something. It is my understanding that in real life you have never processed an actual case. By your own words in other postings you are conducting research and that you are not an actual practicioner. Perhaps, although I doubt it, you may gain from experimentation to find your and I say (empahsis)your scientific findings. There are many who are way ahead of you. By the way your vocabulary is impressive and obviously meant to confuse the issues at hand and in an attempt to demonstrate your intelligence. Quit avoiding issues which you bring up (alledged seeking information) and open your mind. It appears that you like to be confrontational. Good luck in your undertakings and agenda what ever they maybe and grow up. Love to see you in court presenting you personal opinions.