CLPEX Chat Board

I HAVE BEEN PROMOTED TO DETECTIVE SERGEANT AND OUR AGENCY CURRENTLY HAS NO POLICIES OR PROCEDURES ON THE PROCESSING OF EVIDENCE FOR LATENT PRINT DEVELOPMENT, AND I WAS LOOKING FOR A LITTLE GUIDANCE ON CREATING SOME, OR BORROWING SOMEBODY ELSE'S. NEXT, WE ARE GOING TO START USING DIGITAL PHOTOGRAPHY, AND IF ANYBODY HAS ANY POLICIES FOR THE USE OF DIGITAL PHOTOGRAPHY, SAME THING. OUR EMAIL IS HPDDB@HACKETTSTOWN.NET THANKS

HPDDB,

A good place to start would be www.SWGFAST.org. The Scientific Working Group on Fingerprint Analysis Science and Technology defines consensus standards and publishes recommended guidelines for the discipline of friction ridge examination. Another of the FBI-sponsored working groups, SWGIT, publishes imaging guidelines that would assist with your photography task. Their website is: http://www.fbi.gov/hq/lab/fsc/backissu/ ... swgit1.htm

Several people have posted similar requests on this site over the years, and others have contacted them off-line and provided copies of their department SOP's and Policy Manuals. A good double-check as you create your own is to have a copy of the SWG guidelines open in front of you.

I hope your project goes well,

-Kasey Wertheim

Just a head's up on what you may expect from knowledgable defense counsel....

Make sure latents developed at the scene are photographed in place. Ditto evidence from which one might reasonably expect to develop latents. Likewise developed latents should be photographed in place before being lifted. Not doing this leaves you open to suggestions that the evidence or print is a fabrication. (Applies to any photography, but with digital it is cheap to take lots of images.)

Make sure you keep the original digitial images and have solid chain of custody to prove those are unchanged originals.

Make sure you have tracking data for every change made to the digitial images in the course of processing the prints. Some programs will be able to track this for you. These two together will be useful in showing that you did not do something inadvertently (or intentionally) to the latents that results in a false ID. There's at least one case on this point where there were issues raised about harmful effects of enhancing the image where police couldn't explain what they did or how it might have caused problems.

Mr. Cherry, who often posts here, has some strong views about the potential for digial imaging software to create distortions. You may want to talk with your software vendors or someone knowledgable about the intricacies of your software and about the issues he's raised.

Mr. Cherry, who often posts here, has some strong views about the potential for digial imaging software to create distortions. You may want to talk with your software vendors or someone knowledgable about the intricacies of your software and about the issues he's raised.

Although he often posts here, and although he has strong views, that doesn't make his views valid. He has never shown a single example of any software used in the way it was intended, to create the distortions he claims are happening all the time. He has created some examples on his web site that have no basis in real world applications and that actually are falsifications of what they claim to be. I pointed out the false claims of his images currently on his web site.

My point is that I would be concerned with real claims, but I wouldn't be concerned with false claims. There is a big difference.

Lastly, there is nothing that substitutes for good training.

George
Imaging Forensics

I don't have the technical skills to argue with Mr. Cherry and Mr. Reis on the merits of Cherry's concerns. I'll leave that to the digital imaging specialists.

Even if one finds the concerns unsupported, however, it is worth knowing that the argument is out there, that it might be pursued by a defense attorney persuaded by Mr. Cherry's writings, and that if the examiner can't answer the questions raised, the judge or jury may be persuaded that there's a problem with the digital images used. I'd still say it is worth talking to your software provider about the concerns raised so you can say on the stand (1) you checked it out and (2) there was no problem or the methods you use avoid any problems.

A defense attorney will always find something to argue about with or without Mr. Cherry's help. That is after all their job. Common sense and good training are all that is needed with digital photography. If you have the original image, software that tracks image change is not really necessary.

I advise against this practice unless you intend to drag your system into court every time you testify about changes. But if you feel you must use it, Photoshop does it for free so you don't need an overpriced database.

Finally, there are no turnkey systems on the market that can gurantee an unaltered image. This is becasue they apply their "Security" at image download. If someone wants to alter an image they can do it before download and then have the "Secure" database add whatever security to an altered image.

Our lega system is based on the integrity of the indivdual. If you are talking about digital evidence or any other evidence a computer or proceedure will not gurantee authenticity. It will always come down to the integrity of the individual.


Joe Heppler
Digital Imaging Coordinator
Orange County Sheriff Forensic Science
digitallaw@cox.net