What is the fine-grained topic of the following text: In the space of a few hours, two activists belonging to the United People's Democratic Front (UPDF) and its rival group JSS MN Larma, both Chittagong Hill Tracts-based political parties, were murdered in Naniarchar upazila of Rangamati on Wednesday. Only return the topic.
Murder of two activists from UPDF and JSS MN Larma in Naniarchar upazila of Rangamati.