Answer: Case law
Explanation: Case laws are a compilation of reported cases which forms a body of law within a certain jurisdiction. They contain written legal decisions which have been made by a court in the past, and are thus employed in making verdict on current or present cases. In case laws, judges adhere to the principle of making current decisions based on verdict passed on previous related rulings. This principle is called stare decisis. The rule of precedence is employed when security operatives or professionals form part of an investigative panel resulting in the trial of a criminal.