Age Determination of Latent Fingerprints Directly from Forensic Adhesive Tape Using Ultrafast Desorption Electrospray Ionization Mass Spectrometry and Machine Learning

Katherine Margulis, The Hebrew Univ School of Pharmacy, Jerusalem, Israel
Nora Rajs, Forensic Scientist , Israel Police, Jerusalem, Israel
Yinon Harush-Brosh, The Hebrew Univ School Of Pharmacy, Jerusalem, Israel
Ron Raisch, The Hebrew Univ School Of Pharmacy, Jerusalem, Israel
Ravit Yakobi, The Hebrew Univ School Of Pharmacy, Jerusalem, Israel
Amani Zoabi, The Hebrew Univ School Of Pharmacy, Jerusalem, Israel
Guy Nevet Golan, The Hebrew Univ School Of Pharmacy, Jerusalem, Israel
Moshe Shpitzen, The Hebrew Univ School Of Pharmacy, Jerusalem, Israel
Sarena Wiesner, The Hebrew Univ School Of Pharmacy, Jerusalem, Israel
Michal Levin-Elad, The Hebrew Univ School Of Pharmacy, Jerusalem, Israel

Fingerprints provide indisputable forensic evidence for establishing identity. Latent fingerprints, often visualized with black magnetic powder and adhesive tape, can be matched to police databases for identification. However, determining the deposition time is crucial to temporally tie the fingerprints to the crime.  Despite extensive efforts, no reliable method exists for determining fingerprint age. This study presents an innovative technique for directly dating latent fingerprints using ultrafast 2-dimensional desorption electrospray ionization mass spectrometry (DESI-MS). The fingerprints are analyzed directly from a forensic adhesive tape after development with magnetic powder. This method aims to enable the dating of fingerprints collected from virtually any nonporous surface. The study involved 750 fingerprints from 330 volunteers, aged up to 15 days under various conditions. Data analysis using the XGBoost algorithm achieved a correlation of 0.54 for fingerprint age prediction and 83.3% accuracy in distinguishing between 0-4 days and 10-15 days old prints. Key imaging parameters, such as DESI-MS scan rate, mass range, scan area, spatial resolution, and imaging mode, were optimized to enhance age determination precision and support rapid processing within forensic workflows. This research, conducted in collaboration with police forensic unit and academia, integrates seamlessly into practical forensic applications.