Fourier Transform Infrared Reflectance Spectra of Latent Fingerprint: A Biometric Gauge for the Age of an Individual

• NCJ Number: 222349
• Journal: Journal of Forensic Sciences Volume: 53 Issue: 2 Dated: March 2008 Pages: 369-376
• Author(s): April Hemmila B.A.; Jim McGill Ph.D.; David Ritter Ph.D.
• Date Published: March 2008
• Length: 8 pages
• Publication Format: Article
• Publication Type: Report (Study/Research)
• Language: English
• Country: United States of America

Annotation

This study used partial least squares (PLS) regression of 155 fingerprint infrared spectra to compare print chemical characteristics with the contributor's age.

Abstract

The study found that a combination of constituents in fingerprint deposits changed linearly with age, with a significant shift in these constituents around puberty. This study's breakdown of functional groups with age is consistent with the previous studies examined. Young people have primarily free fatty acids in their fingerprint deposits, and older people have longer chain fatty acids that have been esterified with alcohols. The study's results do not identify specific chemical components in the fingerprint mixtures that account for the observed difference in infrared spectra with age; however, the findings do allow researchers to infer some information about relevant chemical classes and to draw comparisons with the existing literature; for example, the 2800-3000 cm-1 exponent region of the infrared spectrum is a significant wavelength range in distinguishing the four age groups: 4-5 years old, 11-14 years old, 18-26 years old, and 29-70 years old. The forensic and dermatological literatures confirm that changes in the proportion of free long-chain fatty acids and their corresponding esters are generally predictable throughout life. These findings suggest that the technique used in this study could be used to provide an age range for an individual fingerprint contributor even though database searches do not provide a fingerprint match. Fingerprints were collected from 78 individuals who ranged in age from 4 to 68 years old. No washing or other preparations were conducted prior to print collection. Each person pressed one finger onto one tin plate. Two infrared spectra were taken of each print. For children 0-19 years old, this was done within 24 hours of the print deposit; for adults 20-70 years old, this was done within 48 hours of the deposit. Details of this procedure are described in this report. 1 table, 6 figures, and 16 references