Enhancing the Quality of Aged Latent Fingerprints Developed by Superglue Fuming: Loss and Replenishment of Initiator

• NCJ Number: 224725
• Journal: Journal of Forensic Sciences Volume: 53 Issue: 5 Dated: September 2008 Pages: 1138-1144
• Author(s): Stephen P. Wargacki Ph.D.; Linda A. Lewis Ph.D.; Mark D. Dadmun Ph.D.
• Date Published: September 2008
• Length: 7 pages
• Publication Format: Article
• Publication Type: Report (Study/Research)
• Language: English
• Country: United States of America

Annotation

Since the cyanoacrylate (superglue) fuming method (CFM) develops fingerprints by growing a polymer coating over the print residue, this study examined how the changes that occurred to a fingerprint residue over time influenced the growth of polymer during print development.

Abstract

The study found that when the dehydration of a latent print was coupled with exposure to light and air currents over time, there were significant decreases in the amount of polymerization and consequently the apparent print quality. The erosion of the dried print by airflow and ultraviolet degradation of the initiators present in the prints apparently results in a loss of the initiators on the print surface as the print ages; this translates into a decrease in the amount of cyanoacrylate that polymerizes off of the aged print and a resulting decrease in developed print quality. A methodology was developed for recovering an aged latent fingerprint’s ability to initiate and polymerize ethylcyanoacrylate by exposure to select vapors. Two enhancement agents, ammonia and acetic acid, were tested for their ability to enhance degraded latent fingerprints. Exposure of the aged prints to both enhancement agents produced increases in the amount of polymerization that occurred during fuming, along with increases in print quality. The enhancement results primarily from a ridge coating process; however, additional studies are needed in order to verify this theory. Due to the greater observed enhancement with acetic acid and the toxic property of ammonia, which may interfere with DNA testing, acetic acid has the greatest promise as an enhancement agent. Description of the study method addresses fingerprint deposition; substrate preparation; fingerprint development by the CFM; latent fingerprint enhancement; and the features of the QCMB (quartz crystal microbalance), a highly sensitive acoustic wave sensor. 1 table, 8 figures, and 11 references