Geographical Information System (GIS) is underutilized within the forensic discipline, especially concerning the discovery of clandestine graves. GIS, viewshed analysis, and probability maps are being introduced into desk-based research both for archaeology and forensic purposes. This study aims to investigate how useful GIS can be to narrow down large search areas when locating clandestine graves. Combining GIS, viewshed analysis, and probability maps allows for the exploration of potential areas of concealment and diggability on Saddleworth Moor to find the remaining missing Moors victim, Keith Bennett. Methods included viewshed analysis consisting of what is visible and not visible from a certain location while the probability map registers the likelihood of penetrability across the Moors landscape. Using two GIS software programs, QGIS and ArcGIS Pro, maps were constructed examining the A635 on Saddleworth Moor and the potential location of Keith Bennett. This takes into consideration the geology, terrain, water networks, and road systems. Analysis of the GIS maps demonstrated that two possible areas were likely to be able to conceal Keith Bennett's body. It then aids to identify areas for further investigation. This study also indicates that GIS data analysis has the potential to aid in criminal and civil investigations and helps narrow down search areas to manageable sizes. Not only does it aid in cold case criminal investigations but it can also be utilized within everyday desk-based research on recent investigations.