Forensic examination of chemically altered documents: Efficacy of acetone, ethanol, DMF and hydrogen peroxide on common writing inks

Forensic questioned document examination has considerable difficulties when handwritten papers are chemically erased. In this investigation, the efficacy of four chemical erasers were systemically assessed on three writing surfaces, associated with five frequently used ink types. Chemical erasers used are acetone, ethanol, dimethylformamide (DMF) and hydrogen peroxide (H2O2) on writing surfaces; A4 paper, cheque paper and bond paper. The Video Spectral Comparator VSC 8000 was used to perform multi-spectral inspection under visible, ultraviolet (365 nm) and infrared (700-1000 nm) illumination on 60 samples that were processed under controlled settings. Visual observations identified that ink composition affects reactions to solvents where oil-based ballpoint inks faded with acetone, ethanol and DMF. Water-based gel and fountain pen inks were resistant to acetone and ethanol. Examinations under VSC8000 showed that organic solvents showed partial recovery under infrared light. Gel and fountain pen inks were fully recoverable revealing text invisible to the naked eye. DMF demonstrated high effectiveness, facilitating fading of all ink types with potential for restoration. The inference from the findings emphasize the necessity of including multi-spectral imaging in forensic document analysis, as visually erased text may include identifiable residues. The current work offers significant insights examining document tampering and aids in the formulation of standardized techniques for identifying chemically modified papers.