CLPEX Chat Board

In my experience, the mis-identification of latent prints has come about when someone tried to match up the detail in the known print (clear print) to the latent print (less clear print). It is an easy thing to get caught up doing. You start out with the latent ( or less clear print) comparing it to the known (more clear) then instead of going back to the latent ( or less clear) you continue switching back and forth. I've wondered if that was the case in the Madrid incident?

PCC wrote:In my experience, the mis-identification of latent prints has come about when someone tried to match up the detail in the known print (clear print) to the latent print (less clear print).

Out of curiousity - how many latent mis-identifications do you have direct knowledge of in your experience?

And how do you know that they tried to match up the detail in the known print to the latent print?

It's very rare to find this information documented in a typical case, let alone in cases ultimately ending in mis-identification. And if it wasn't documented, did the examiners explain that this was their process during the examination that ultimately mis-ID'd?

I don't have much firsthand knowledge of mis-ID's, and those that I am aware of directly didn't have any information stating that they went from known to latent.

In the past 20 years I have come across approximately 5/6 mis-identifications when verifying the positive comparisons made by others. I also know that there are others in my department that have done the same. Nearly all of the mis-identifications I verified were done by those still in training. In each case when I Looked at the detail they considered "points of identifcation" there was NO WAY I would have seen them as such, but when I looked at the known print I saw what they were trying to match up. When questioned, most confirmed my suspicions, the others couldn't give me much of an answer at all. I do not know of the reasons given for the mis-identifications that I didn't verified, but I do have my suspicions.

There are a variety of reasons that unconciously suck a person into the area of misidentification. A desire to catch the bad guy, or to be a hero, or to clear out a case, etc. I think it is imperative that you determine it is in fact minutia before you look for any corresponding minutia. Since in the known print it is generally easy to spot what is true minutia, we have our people look a the latent to make the determination and then match it to the known. Of course there are times you come across discrepancies in the known print or the latent that will have to be addressed. Still, we continue to complete the comparison from latent to known and the discrepancies will need to be addressed before we render a final decision.

I don't have any knowledge of any mis-identifications where they applied this system. On the other hand, looking at the high profile cases involving mis-identifications, some of the minutia marked I would NEVER have considered, so it makes me wonder...is it because I am not looking at the original evidence, or is it because they were matching the known print to the latent?

PCC wrote:I don't have any knowledge of any mis-identifications where they applied this system. On the other hand, looking at the high profile cases involving mis-identifications, some of the minutia marked I would NEVER have considered, so it makes me wonder...is it because I am not looking at the original evidence, or is it because they were matching the known print to the latent?

I look at similar, probably the same things, and I have to suspect a combination of factors. I, too, am tempted to think that those features could never have been honestly misinterpreted, but I also see, in this and other human endeavors, where once someone has pointed to the error, they're easy to see. And we see this sort of thing so often that it's not only hard to believe they're deliberate, but when the individuals are known, it seems most unlikely. We could perhaps be more comfortable if they were done with bad intent. But that's too easy an out. What I get from these is a warning that there is a risk of subtle influences working to create a chain of errors that has, in at least come cases, caused otherwise highly experienced and thoroughly trained examiners to sponsor error. I do think that one factor is often letting the record print influence interpretations of latent features. I also don't suspect it to be a frank reversal of direction. I have to suspect it is more that a circularity creeps in. It would also be comforting if it was happening to the most inexperienced or ill-trained examiners. That's often not the case. I have been unable to think of anything that would prevent such errors or would at least tend to bring an examiner to recognize an incipient error than insisting upon certainty of interpretation of the latent in isolation and rigorous refusal to revise that interpretation under the influence of the record print. Obviously, genuine mistaken interpretation may be discovered and corrected to make an identification, and the record print may be part of what triggers the reinterpretation. In those case, I believe it's appropriate to articulate just how that happened, even if only for one's own reflection on the formal narrative of what happened, being very aware of the hazards.

I also think it's unavoidably true that, for every revealed erroneous identification that isn't plain old "oops!" or simple incompetence, there must be many other identifications that were made based on ambiguous features of the latent but that really should not have been made - but that largely due to the circumstances of the work, the individual was the actual source. And, if we are honest, we have to admit the possible case in which the identification was erroneous, but we will not know, because the defendant admitted guilt, either as a matter of fact or, more rarely, out of a belief that conviction was inevitable. The errors of inappropriate certainty simply cannot be imagined to exist only in cases that lead to erroneous identification. I think that's exactly why they appear in the erroneous cases. Because they are being made, to some degree, across all cases.