The use of collective graves is one of the main features of the western European Late Neolithic. A single gravesite received the successive deposition of dozens or sometimes hundreds of individuals. While cremations or even full-fired inhumation layers are often found within these funerary deposits, the actual role of fire is still poorly understood. Recently discovered within the important archaeological complex of Passy (Yonne, France), the burned collective grave of La Truie-Pendue provides an outstanding case study to examine the use of fire within Neolithic funerary rites. In this study, we develop a new contextual approach to bone alterations in order to reconstruct the original circumstances of combustion and to examine cultural motivations for the use of fire. Results of spatial statistical analyses indicate that the fire event was the first step of a procedure that sealed the grave, closed the access to the dead and signaled the end of the grave's history. Similar sealing procedures were usual elsewhere during the Late Neolithic. Finally, this study demonstrates the value of using GIS as a tool to optimize taphonomic analyses of widely fragmented and commingled skeletal assemblages.