Sociologists increasingly understand the mutual influence between legal change and social movements; indeed, some social movements are pursued primarily through the judicial system as impact litigations, and require reinterpretation of statutes to succeed. When examining such cases, scholars often focus on doctrinal innovations introduced by higher hierarchies of courts as the Supreme Court and the Courts of Appeals. However, such a perspective overlooks the adaptation and innovation of legal principles in lower-level courts. Adaptation to new doctrinal changes is not an immediate process, and judges at lower levels can continue to adhere to their established practices; conversely, innovations made by appeals courts can not immediately reorient judicial practice in all realms. This study uses computational methods to analyze the change across all American District Court since 1960s for a substantively important area of law: police misconduct. Social movements that aimed to boost civilian control of police received a major boost when this was reconceived in terms of civil rights, as opposed to, say, organizational corruption. But setting our eyes aside from landmark Supreme Court rulings, where and when did this change originate, and how did this change diffuse through different levels and spaces of the judicial system? By combining case citation analysis and structural topic modeling (STM), we can reproduce the logic by which appeal judges reached for, and reinterpreted, different cases as precedents as they worked to conceptualize police misconduct in ways that appeared better suited for emerging social conditions.