title: Determining the chronology of deposition of natural fingermarks and inks on paper using secondary ion mass spectrometry.
abstract: This study thoroughly explores the use of time-of-flight secondary ion mass spectrometry (ToF-SIMS) for determining the deposition sequence of fingermarks and ink on a porous paper surface. Our experimental work has demonstrated that mapping selected endogenous components present in natural fingermarks enables the observation of friction ridges on a laser-printed surface, only when a fingerprint is deposited over this layer of ink. Further investigations have shown limited success on ink-jet printing and ballpoint pen inks. 51 blind tests carried out on natural, latent fingermarks on laser-printed surfaces; up to 14th depletion with samples aged for up to 421 days have resulted in a 100% success rate. Development with ninhydrin was found to affect the fingermark residue through mobilisation of ions, therefore sequencing determination was compromised; whilst iodine fuming and 1,2-indanedione developers did not. This implied that selected development methods affected success in fingermark-ink deposition order determination. These results were further corroborated through inter-laboratory validation studies. The adopted protocol and extensive series of tests have therefore demonstrated the effectiveness and limitations of ToF-SIMS in providing chronological sequencing information of fingermarks on questioned documents; successfully resolving this order of deposition query.
authors: Experimental Techniques Centre (ETCbrunel), Brunel University, Uxbridge, UB8 3PH, UK. nicola.attard-montalto@brunel.ac.uk.
authors: Nicola
authors: N
authors: Attard-Montalto
authors: Jesús J
authors: JJ
authors: Ojeda
authors: Alan
authors: A
authors: Reynolds
authors: Mahado
authors: M
authors: Ismail
authors: Melanie
authors: M
authors: Bailey
authors: Lisette
authors: L
authors: Doodkorte
authors: Marcel
authors: M
authors: de Puit
authors: Benjamin J
authors: BJ
authors: Jones