Crime definitions for murder, sexual assault, and arson are taken from the FBI's Uniform Crime Reporting Program. In the first part of the manual, these three major crime categories are classified according to defining characteristics, victimology, crime scene indicators, forensics, and investigative considerations when applicable. Case illustrations are presented for each classification. The second part of the manual presents a review of the study of crime. Key concepts in the decision process are addressed for classifying a crime, the detection of staging and personation at the crime scene, the modus operandi, the signature aspects of violence crime scenes as well as crime scene photography, and prescriptive interviewing. The role of the FBI Academy's Investigative Support Unit in assisting law enforcement is discussed. The numbering system for the basic classification consists of three digits: The first digit represents the major crime category, the second digit for further grouping of the major crimes, and the third digit is the specific classification within these groups. Further subdivision into subgroups uses two additional digits following a decimal point after the code. As other major crime categories are classified, appropriate identification codes will be assigned.