Comparative Study of the Development of Latent Impressions on Gloves
Written by Cierra Wiggins & Andrew R. Reitnauer   

PHYSICAL EVIDENCE is a common occurrence, most likely found at every crime scene. Each piece of evidence may provide investigators with probative information regarding the circumstances of the event, or the presence of a specific person. The use of gloves is often used in the commission of a crime, and often collected by crime scene responders for forensic examination and analysis.

While gloves primarily serve as a barrier between the skin and the surface being touched, latent impressions may be deposited on the gloves during use and may be developed and utilized as a piece of physical evidence. The sequential examination process utilized during this type of latent print processing may vary, based on the desired contrast of the impression to the background and the target matrix of the technique utilized.

This study examined two types of gloves—laboratory nitrile and latex—that may be accessible and commonly encountered during the investigation of a crime scene. They were also processed using different sequential techniques to examine the developmental process, as it pertains to the retained matrix of the transferred latent impression. The reagents used for this examination consisted of: cyanoacrylate (CA) fuming/dye stain, CA/WetWop, gentian violet (GV), and magnetic powder. Results suitable for collection were photographed and analyzed for sufficiency. Resulting data was compared to establish the clarity of examination methods.

Materials and Methods

This study focused on the processing of nitrile and latex gloves for each of the sequential development techniques. A total of six of each type of glove were worn by two separate donors for approximately 15 minutes, totaling 12 gloves per processing reagent. The gloves were carefully removed and stored for 48 hours prior to processing.

The cyanoacrylate process was performed using a Foster + Freeman MVC3000 cyanoacrylate chamber in accordance with current laboratory protocols. A test print deposited using a Sirchie latent print standard pad was placed on a black fingerprint lift card, to be run concurrent during the fuming process to ensure development. The fluorescent dye stain utilized was methanol-based RAM. The gentian violet, RAM, and black magnetic powder were all manufactured by Evident. The black WetWop utilized was supplied from Lightning Powder. A SPEX Crimescope was used to view any development following the application of RAM in the following wavelength and barrier filter combinations: 415nm/Yellow, 455nm/Orange, and 515nm/Red. Resulting photographs were captured utilizing the Foster + Freeman DCS5 with a Nikon D5 digital camera.

Results

The donor gloves were processed using the development sequences previously described. Following the application of the four sequential methods on the donor gloves, some overall general results were observed, as discussed below:

• CA/RAM

All nitrile gloves developed friction ridge detail, best observed under 455nm/Orange barrier filter criteria. The anatomical area yielding the most consistent results were in the palm regions. As the finger areas began to introduce some textures within the substrate, it could be a contributing factor to the decrease in suitable latent print detail. The latex gloves did not consistently yield suitable developed impressions, and often failed to yield any visualized ridge detail.

• CA/WetWop

All nitrile gloves developed suitable latent impressions. In these samples, friction ridge detail was developed consistently in both the palm regions as well as the fingers. The latex samples did yield some developed latent impressions, however the results were not as consistent as with the nitrile samples.

• Gentian Violet

The nitrile gloves were inconsistent with their developed results. Some samples yielded some observed features; however, they were mostly creases and not developed friction ridges suitable for comparison purposes. A contributing factor may have been the lack of contrast between the glove and the development technique itself. All of the latex gloves yielded positive results when treated with gentian violet independently. Additional samples that were created and sequentially processed with CA/gentian violet yielded no discernable ridge detail, possibly due to the absorption of the gentian violet reagent into the deposited cyanoacrylate residues.

• Magnetic Powder

The magnetic powder did develop discernable ridge detail on both types of gloves; however, the results were deemed to be of higher quality on the latex gloves than the nitrile gloves. A potential reason for this development may be the reduced contrast between the glove and the powder development, and possibly the introduction of textures in the finger areas of the gloves.

The photographs below are a depiction of the typical results obtained through the sequential development processes, as previously described:

Figure 1. CA/RAM-developed impression on nitrile glove, visualized under 455nm/Orange barrier filter.

Figure 2. (A) Gentian violet stain on used latex glove.

Figure 2. (B) Enhanced latex GV latent impression.

Figure 3. Magnetic powder developed impression on latex glove.

Figure 4. (A) WetWop powder used on CA fumed nitrile glove.

Figure 4. (B) Enhanced Nitrile CA/WetWop developed print.

Conclusion

Based on the data collected, it was observed that there was an overall trend in the development of latent impressions within the types of gloves. Overall, the nitrile gloves had a more consistent developmental reaction to the reagents used as compared to the latex gloves. The sequential examination process of CA/dye stain consistently resulted in a development of impressions suitable for further examination, in contrast to the latex gloves. Gentian violet, used primarily as a development technique on adhesive surfaces, also resulted in a consistent positive reaction on the latex gloves for the development of suitable friction ridge detail. In contrast, gentian violet applied to the nitrile glove did not provide the contrast needed to visualize a developed latent fingerprint, but it did allow for the visualization of the creases present in the donor. The application of black magnetic fingerprint powder did yield a positive development on both types of gloves, allowing further examination to be performed. The sequential application of WetWop did develop suitable impressions on both types of gloves, allowing this technique to be used on both varietals.

During the processing of evidentiary items, a number of factors may affect the recovery of latent impressions on a surface. When considering the surface of disposable gloves, there may be an increase in moisture from the containment of sweat exuded from the palmar surface of the hand that could compromise the individual characteristics of the friction ridge skin. Adversely, if gloves have been changed during use, the surface of the skin may become dry and not have enough matrix to transfer onto the glove to leave a suitable impression. As individuals are wearing these types of gloves, additional distortion may occur within the transfer of the friction ridge characteristics due to pressure, as well as increased lateral and rotational distortion. As these gloves are manufactured to serve as a protective barrier between the wearer and the materials being handled, the material the gloves are manufactured from is made to resist moisture. Thus, the impressions left by the eccrine perspiration of the palmar surface of the hand is fragile, and can be negatively impacted by external factors.

During the course of this study, there were some potential factors that could have affected the results, or that could have been enhanced to further examine the scope of these processes. Any variation in the perspiration levels from the donors; friction caused during removal or movement; and additional variables could have affected the deposition and retention of the latent print detail on the gloves. Additional research may be warranted to examine these factors.

Additional Information and Acknowledgements

The authors would like to thank the Washington DC Department of Forensic Sciences, Latent Fingerprint Unit for their support in this study, as well as Trinity Washington University and the NASA DC Space Grant Consortium.

About the Authors

Cierra Wiggins is a native resident of the Washington, DC area. Wiggins is an alumna of DC Public Schools and is currently a rising senior at Trinity Washington University majoring in Forensic Science. Cierra’s interest in forensics began while taking a forensic science course in high school. From that class, she decided she wanted to pursue a career in crime scene sciences, evidence processing, or working for the Innocence Project. Cierra is currently a Latent Fingerprint Intern at the Department of Forensic Sciences in Washington, DC.

Andrew R. Reitnauer is the Technical Lead Scientist (Fingerprints) with the Washington DC, Department of Forensic Sciences. He is a practicing forensic scientist with 13 years of experience as a supervisor, latent print examiner, and senior crime scene responder. As a technical leader and primary trainer within his laboratories, Reitnauer is responsible for procedure development, and development of the evidence processing program. He is an ASCLD/LAB-approved internal auditor for laboratory standards. To date, he has examined evidence in over 15,000 cases, 150 crime scenes, and has been qualified as an expert witness in courtroom proceedings approximately 85 times.

References

Pleckaitis, J. (2007) Developing Friction Ridge Detail on the Interior of Latex and Nitrile Gloves. Journal of Forensic Identification, 57(2).

Pressly, J. (1999) Ninhydrin on Latex Gloves: An Alternative Use for an Old Technique. Journal of Forensic Identification, 49(3).

Reitnauer, A., C. Lahm. (2015) The Use of Colored Barrier Filters in Forensic Photography. Fingerprint Whorld. 40(158).

This article appeared in the Winter 2019 issue of Evidence Technology Magazine.
Click here to read the full issue.

 
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