From Peirce to Rithy Panh. This article examines how documentary film might be seen as a way of exploring a semeiotic account of memory. It argues that memory is to be considered as something that is active and communicable within a social context. This is explored through an engagement with Rithy Panh’s S21 : The Khmer Rouge Killing Machine (2003), which highlights the dialogical nature of memory and the interconnection between infrasubjective and intersubjective memory. These connections are created through both the overall narrative structure and individual formal strategies within the frame and composition. Memory is thus reconfigured as not something that is absolutely private. Rather, it is now part of a wider social dialogue that needs to take place in the aftermath of genocide.