Infrared and Raman spectroscopy in conjunction with chemometric methods in questioned document analysis: Forensic applications

The manipulation of documents remains a common tool for fraudulent activities, encompassing disputed signatures, threatening letters, counterfeit currency, false medical documents, cloned cheques, and forged security documents. With technological advancements, document creation has evolved from manual handwriting to computer-generated formats, employing various devices such as printers, photocopiers, scanners, and multifunctional devices globally. Forensic document examiners grapple with these challenges, and ongoing efforts are dedicated to addressing them. This study provides a comprehensive review of publications from the past decade, focusing on dating studies, ink and paper analysis, examination of writing and printing inks, ink analysis of questioned documents, and research on intersecting lines. The central emphasis lies on the utilization of Infrared and Raman spectroscopy within the domain of Vibrational spectroscopy. The review also highlights current trends, major challenges, and the effective application of chemometric approaches in this field.