CLPEX Chat Board

This is all hypothetical:

Scenario: A salesman is in town and the stuff he sells is “a girl’s best friend”. He makes a stop in the evening to eat. Part way through the meal he hears what he thinks is his car alarm. He goes outside to see a subject running away with his brief case. He starts to give chase but decides against it. Coming back to his car he sees the passenger window broken, pushed in and his brief case missing so he calls 911. Police respond and ask for a CSU. The PCT arrives and observes the shattered window, and an old tire tool beside the car. In processing the shattered safety glass a palm print is recovered on the exterior of the passenger window and on the lift indications are made as to which end is facing up. The PCT submits the latent lift and photos plus completes their report. The next day a LPE receives the case and has been told this is a priority. A search through the local palm print data base yields a record that shortly is determined to be a match.

Observation: Upon looking at the lift from the shattered safety glass one can see small cracks throughout the lift. It is an impression of the left hand from the base of the palm of the hypo-thenar and more than half of the hypo-thenar is present. Darker ridges at the base to lighter ridges towards the interdigital. The location marks indicate that the top of the palm was pointing towards the roof of the car. On the far left side of the palm are three wider cracks where the adhesive has stretched causing a gap (small gap—about 1mm or 1/10 of cm wide). The largest of these gaps run the length of the latent print and cuts across about 36 friction ridges.

Question 1: If I could show that on the larger of the 3 gaps that there are missing parts of the ridge features on 4 ridges (ie the fork of a bifurcation, the hook of an ending ridge, a short ridge half its length, etc) could someone say with a high level of confidence that the palm print was left on the window after it was shattered and not before it was shattered?

Question 2: Does anyone have material or articles on such a situation. Now I have the one on the plate glass that was published in the JFI a year or two ago, but does anyone have material or have done case work on what I have described.

Question 3: Is this hypothetical LPE out of their mind and need to send it to an experts expert? Is saying such a thing in violation of the code of ethics?

Of course this is a hypothetical case and no real case of this type exists.

Charlie,

Certainly an interesting hypothetical case. Hypothetically here are my thoughts...

The concept involves anotomical aspects of friction ridge skin, physics of touch, and good ole' common sense. I think the hypothetical examiner is well within his (or her?) rights to apply these principles to the examination. In fact, in your sceniario it appears that this has already occurred, and the question is whether (and how) to report the conclusion that has already been reached. In fact, I would take it a step further and say that if the examiner didn't report the conclusion that he (or she?) had already made, that they would in fact be facing another dillema of perhaps just as much importance (witholding evidence).

The analysis of the latent is what should hold the key, hypothetically. How thick are the ridges as they approach the apparent gap in the substrate. At the very edge of each side of the substrate, to the ridges thicken or thin? Does this support or refute the hypothesis that the substrate was disconnected during deposition? Now for the physics part... is it anotomically possible for the substrate to be connected and for a single deposition to result in the gap that truly does exist based on observation? If not, is there any indication of a double touch? Does your analysis support or refute a single-touch deposition across the entire print?

This would be a neat hypothetical case to see published some day, along-side a thorough analysis and conclusion.

-Kasey

Charles,
This is not prcisely on point, but perhaps of some interest.

I'll combine an actual case I was involved in from 1979 with a hypothetical scenario (due mainly to my fuzzy memory on many of the details, & I no longer have access to the documentation). I remember the year because the IAI conference was in Phoenix at the time, & played a role in the examination.

Hypothetically there was an apparent one vehicle roll-over accident in relatively remote off road area. A deceased victim (not the vehicle's owner) was found at the scene. The vehicle was reported stolen in the AM hours, after the accident scene had been discovered, but prior to contacting the owner. The teenage son of the owner had used the vehicle the previous evening, and reported having returned home approximately 1:00 AM. The deceased victim was found to be a classmate of the owner's son, although apparently not a close friend.

An examiner responded to the scene to process the vehicle for latent prints, and developed multiple latent prints. The dynamics of the damage to the vehicle were such that if there had been a second, surviving occupant of the vehicle, their only exit opportunity would have been through the front passenger door window, which was open.

A few latent prints from the vehicle, all from the front passenger area, were identified to the deceased victim. Some latent prints were identified to the owner's son, both in the driver's area, and including one identifiable print that crossed over some 'fractured paint' over bent metal on the outside of the front passenger door.

Although the position of the print on the passenger door was consistent with climbing out of the vehicle after the accident, it was not conclusive. The latent residue as represented in the latent lift was examined microscopically with a new new stereo zoom microscope on display at the IAI conference, and it was observed that the residue spanned uninterrupted across the 'fractures' in the paint, suggesting that the latent print had been placed on the surface after the accident and resulting 'fractured paint' occurred. Several attendees at the conference were consulted informally, and the consensus was the observations were accurate and should be reported.

Subsequent experimentation indicated that depending on the constituents of the latent residue, some elasticity of the residue might be present, but not enough to account for uninterrupted spanning of gaps in the fractured paint, some of which were approximately 1 mm.

The results were reported, but the examiner never had to testify. Unfortunately, no paper was written regarding the case.
Regards, RLT