By advising its supervisory employees of the necessary procedures for researching and documenting incidents that involve force, a corrections agency can take an active role in the investigations of inmates' claims. Because the fact-finding process used by lay investigators may not ensure a thorough explanation of events, IST is an important tool for ensuring fairness in such cases. Issues that should be addressed in an agency investigation are the identity of the aggressor in a physical altercation, the amount of force actually used, and compliance with agency policy. Step-by-step the investigator should document the officer's actions in the context of the facility's written guidelines and State law. Other aspects of an investigation are the evaluation of inmate witnesses' statements, a description of events preceding the use of force, and a determination as to whether any weapons were used. The facts and circumstances must show that the amount and type of force used was consistent with the force needed to accomplish the objective under the circumstances. In all cases, force must be used only within the circumstances permitted by law and within agency guidelines.