Post Number: 59
|Posted on Thursday, August 03, 2017 - 12:03 pm: ||
During training classes and presentations I have given over many years, I often explained that prints can be deposited by persons wearing just one pair of surgical gloves in a manner similar to what happens when you use a sheet of paper and crayons or charcoal to make rubbings from a headstone in a graveyard.
A crime scene technician (or criminal) wearing a single pair of surgical gloves may grab a doorknob which may not have been thoroughly cleaned for months or years, receiving contaminant deposits on the exterior surface of the thin gloves consistent with the underlying friction ridge skin (like the rubbing produced on paper from a gravestone).
Then, when the glove wearer touches other relatively smooth and clean surfaces, the contaminates (representing the raised ridges) can transfer to leave identifiable latent prints.
I might be confabulating, but my recollection is that I first learned of prints through surgical gloves from Bob Olsen at the Army Crime Lab (USACIL/DFSC) circa 1976.
According to several online sources, surgical gloves originated in the late 1800s. One of the earliest published mentions of fingerprints through gloves was on page 3 of the August 1935 edition of the IAI's "Sparks from the Anvil" where there is a brief mention that "Experts are also working on a method for developing prints left through gloves." "Sparks from the Anvil" was the IAI's official publication before "Identification News," which eventually morphed into the "Journal of Forensic Identification" (also known as the JFI). The 1935 cryptic mention of research might have been referring to latent fingerprints deposited "through gloves" or might have been referring to attempts to develop fabric, leather and other glove impressions.
In a 2006 JFI article titled "Concerns When Using Examination Gloves at the Crime Scene," authors David A. Lounsbury and L. Frank Thompson explained how their experiments showed prints could be inadvertently deposited at crime scenes by technicians wearing just a single layer of surgical gloves. The conclusion paragraph of their article includes the following text:
"...when the outside surface became contaminated with a transference material, the glove membrane was sufficiently thin and of a density that allowed the glove to transfer the friction ridge shapes to the substrate. Although the glove may provide adequate protection from chemical or biological hazards for personnel, it is insufficient to protect the crime scene from friction ridge contamination.
Glove protection protocols to avoid latent print contamination is critical. Either a double glove should be worn or cotton gloves should be worn underneath the vinyl glove shell. The double glove method may be less comfortable because of the amount of heat it generates. Both the double glove method and the wearing of a cotton under-glove proved effective in keeping inadvertent latent prints by the crime scene personnel from contaminating the crime scene. Single glove wear, and in particular, vinyl examination glove wear, could significantly contaminate fingerprint evidence that is handled by crime scene processors at the scene."
[from Journal of Forensic Identification, 2006, 56(2), pages 179-183]
Most forensic science protocols recommending double-gloving versus single layers of latex (or other surgical types of gloves) cite the need for protection from dangerous body fluids and other hazards at crime scenes, not the need to preclude accidental deposition of technicians' or investigators' latent fingerprints.
In a 1989 article in the American Journal of Infection Control, J DeGroot-Kosolcharoen, et al reported the following:
Two thousand four hundred medical gloves were evaluated for leakage. Types of gloves examined (number of brands) included sterile latex (seven) sterile vinyl (four), nonsterile latex (six), and nonsterile vinyl (seven). ...Only four brands of sterile latex surgeon's gloves proved nonpermeable to water and blood. Other brands showed leakage that ranged from 1% to 52%. ...These findings affirm that gloves can be regarded only as a means of reducing the risk of gross soilage from blood or body fluids.
[from an abstract on the NIH website at https://www.ncbi.nlm.nih.gov/m/pubmed/2774291/
|Posted on Friday, May 26, 2000 - 11:51 am: ||
It is possible for latent print residue (eccrine gland secretions or contaminants that may be on the hands) to permeate thin latex surgical type gloves.
It is also possible for the exterior of the gloves to pick-up contaminants in a configuration matching the underlying ridges. Sometimes this happens because the gloves may hug or conform to the ridge shape. More often, it is a result of the local pressure exerted on the glove by the underlying ridges along with an ideal viscosity in the contaminant (almost dry oily residue, greasy dirt, etc.) on the surface touched. The result in these (non-permeating) situations is not latent print residue transferring through the gloves, but the gloves acting like a rubber stamp.
|Posted on Friday, May 26, 2000 - 10:02 am: ||
I was watching this show on A&E...this person wore latex gloves and robbed this house. He touched everything in the house, but the police still caught him. Did his fingerprints go through the gloves ???