This document summarizes a case study on encroachment within Bukit Barisan Selatan National Park in Sumatra, Indonesia. It finds that law enforcement alone is not effective at preventing encroachment due to corruption and the influence of local elites. Encroachment levels vary between villages based on differences in patrol frequency and sanctions. While law enforcement targets individual squatters, the roles of local elites who both support and neglect park protection policy must be considered. Conservation policies need to take into account the social and economic needs of communities living near the park.