Evaluating latent prints

[Larry Mazzola]

Does anyone know of a system to evaluate or rate latent prints with reference to clarity and quantity of details that can be used by or taught to the crime scene tech? i.e. to help them with deciding when to send prints to the lab or what to tell investigators when they get prints as opposed to are the prints of value?

[Whisler]

The quick and easy reference in my opinion would be for them to submit any latent lift they see that contains at least two ridges they see running parallel (basically anything to rule out something beyond a splinter or scratch on the substrate). The reason being, is that once you get the latent cards turned in and enhanced with AFIS or some other software, who knows what else you might see.

I personally wouldn't try to complicate the process with formulas and rating systems in the field. Levels of suitability are already complicated enough once the prints make it to the examiners desk.

[Charles Parker]

A tough topic. I am surprised someone did not try to tackle the problem of "Pre ACE" evaluation.

The old standard: On borderline latent prints keep it open, because during comparison you will generally see two or three more features (events).

The new standard: Keep it all since there may come that situation where it can be compared for exclusion but not for individulization.

The A standard: Turn it all in because only a well training, qualified, professional Latent Print Examiner can make that decision.

A number of years ago there was an interview of about 9 well known Latent Print Examiners and the title was "Philosophy in the Field of Identification". One of the questions asked was what to do with "No Value" latent prints. You would be surprised how many said to destroy them if they are of no value. If something today is submitted as no value there would not even be a consideration in destroying it. At least I do not think so.

Does anyone out there destroy no-value latent prints once they have been submitted as evidence?

[Cindy Rennie]

As far as I know (which may not be as far as I think it is!) our "SOCO" officers (semi-trained uniformed officers) are told to lift anything that might be a fingerprint. The full-time FIS officers go through the lifts and decide what is good enough for AFIS and what is suitable only for comparison to a suspect. The rest is marked as "insufficient detail".
All of the lifts are retained, however, even the insufficient ones.

I would think that destroying lifts would raise a red flag to the defense lawyer, who would be able to imply that you destroyed evidence that might have exonerated his client.

[Heidi Fraser]

Yes, I agree with Cindy. I've always heard that anyone in the field without the experience and training to make the determination themselves is told to keep anything where they can see ridge detail, thus leaving it up to the experts to determine value/no value. I've kvetched about this a few times in that sometimes lifts are submitted to us that are simply ridiculous (i.e. yes, there ARE two ridges visible, but no one in their right mind would think there was enough detail there to individualize, or even exclude). But the risk of having someone make the wrong call and throw out something good is worth having to sort through some of these awful lifts, which, after all, are pretty quick to slap a "no value" on and move on.

I would also agree that destroying evidence of any kind (even no value) is just a bad idea in general. Unfortunately, once the lift has been made and submitted, that card is permanent evidence.