Comparison between digital and non-digital bloodstain pattern analysis methods: a scoping review

Bloodstain Pattern Analysis (BPA) is an interdisciplinary or multidisciplinary branch of forensic science that combines physics, biology, and chemistry to comprehend blood patterns and reconstruct the events at a crime scene. Although the development of digital tools (e.g., HemoSpat, BackTrack, FARO Scene, HemoVision) is rapid, the synthesized evidence is also lacking in terms of efficacy and precision. The ability to be integrated into the forensic workflow reveals an acute gap between digital and traditional non-digital methodologies (e.g., stringing, luminol). This scoping review synthesises the evidence to fill this gap, informing the use of evidence-based tools in better crime scene reconstruction and court reliability. Scoping reviews are the most appropriate method of mapping the extent of evidence on new techniques in BPA research. The proposed scoping review will determine the effectiveness, precision, and usefulness of these techniques in forensic working procedures. The search was conducted in the Embase, Scopus, and PubMed databases to identify peer-reviewed articles published between January 1, 2008, and December 31, 2024, in accordance with the principles established in the framework of Arksey and O’Malley and the Joanna Briggs Institute (JBI). Two independent reviewers screened titles, abstracts, and full texts based on inclusion criteria (e.g. primary research on BPA methods, English language). The study’s features, method accuracy, limitations, and workflow applications were considered, and a thematic synthesis was employed to identify the main patterns. After screening and exclusions, 36 studies were included from 180 articles identified (e.g., excluded primary research, non-English articles). Digital systems like HemoSpat and FARO Scene were discovered to estimate the area of origin (AO) much more accurately than manual systems, and their error rates were low (as low as 1.3 mm in HemoVision 3D reconstructions). Digital methods are limited in their application to complex surfaces (e.g., porous or irregular materials). The non-digital techniques, including the luminol, are best at detecting latent stains, but are not specific in their ability to reconstruct the event. The two methods share the issues of standardisation, complexity of the process, and user variation, which influence overall reliability. The scoping review proposes that digital tools of BPA, which are grounded in 3D scanning and machine learning, are more precise than traditional tools; however, they require higher standardisation and need to become more accessible to a broader population. Other deficiencies are non-linear guidance of paths and real-world testing. The implications of these findings are valuable to crime scene investigation as training, policy, and hybrid tools should be developed to improve the equity and admissibility of the investigation process in various international settings. To enhance the applicability of these investigations in a global context, future research should focus on developing user-friendly interfaces, integrating with mobile devices, and integrating with forensic processes. • Bloodstain Pattern Analysis uses digital (such as HemoSpat and HemoVision) and non-digital tools (stringing and luminol) to support forensic analysis, yet their reliability and ease of use are mixed. • There are not many comprehensive studies of Bloodstain Pattern Analysis tools, which means they should be assessed for their effectiveness, accuracy, and how well they fit into forensic procedures. • These tools are helpful in various places (labs and crime scenes), but their use can be different depending on the country and the resources it has.