Radicalization is an aspect in the development of homegrown terrorists; however, researchers have been unable to establish a path to radicalization, uncover how individual and social factors influence radicalization, and identify how the Internet and social media mediate this process. The purpose of this case study was to explore individual and environmental factors that contribute to the radicalization of U.S. homegrown terrorists and identify interventions. Conversion theory was used to develop an understanding of the radicalization of U.S. homegrown terrorists. Data were derived from interviews of local and state law enforcement, military antiterrorism officers (AT), and security personnel from military installations in Eastern North Carolina. Data were analyzed applying content directed and In Vivo coding. The study results helped formulate recommendations on interventions to stem radicalization, identified the news media as a gateway for radicalization, and suggested the incorporation of perspectives from other radicalization-related theories into the conversion theory radicalization model to examine known cases of homegrown terrorists and test its viability as a model to understand radicalization. The results of this study could bring about positive social change by improving relationships and collaboration between law enforcement and community stakeholders, which might generate strategies that could exert greater influence in dissuading individuals from becoming radicalized.