Standard investigative practice calls for the security officer to attentively protect the crime scene and preserve the evidence. “Collection, preservation and the assurance of evidentiary integrity” 1 are central to the investigative regimen. This is true in any type of case consisting of criminal conduct or civil injuries; insurance investigations for arson, fraud, and vehicular accidents; terrorist acts; bomb threats; executive protection threats; intrusions into hotels and motels, colleges and universities; violent labor disputes; workers’ compensation, as well as suspected retail theft. The skills and competencies required of a public police officer apply equally to the private security officer and investigator. This chapter presents a comprehensive analysis of methods and techniques employed by security investigators that insure the integrity of evidence during the collection process and the continuing preservation of the scene.