Criminal Investigation

Criminal investigations are conducted at all government levels in the United States—by federal and military agencies, by state agencies, and by county and municipal agencies. The types of investigations conducted by these agencies are defined by specified legal and geographic jurisdictional responsibilities. For example, a federal agency may have the responsibility to investigate violations of certain federal laws throughout the United States (i.e., the Federal Bureau of Investigation [FBI] can investigate violations of various federal laws) but may be limited with regard to investigating violations of state laws. The mandate of local sheriff or police agencies to investigate violations of state law may be much broader, but their authority may extend only to the geographic jurisdictional limits of the county or city in which they are located. The focus here is on the criminal investigation process of county and municipal law enforcement agencies because those agencies are the most numerous and are responsible for the bulk of the investigative work done within the U.S. criminal justice system.

Criminal investigation involves the use of social control agents to solve crime. The key participants in the process of solving crime are victims, offenders, witnesses, informants, the police, forensic specialists, prosecutors, and judges. These people are involved in gathering and assembling information to reconstruct the illegal activities of offenders. In general, this process starts with a citizen's decision to report crime and ends with the prosecution of an offender. Therefore, the police criminal investigation process can be described simplistically as the collection and use of information to solve crime. Information is broadly defined here as the knowledge of opinions, facts, and/or data, the source of which is either people or things. The collection of information relates to the interface between the police and the public—how the police recognize, detect, identify, and obtain crime-related information. The use of information relates mainly to how police use information within the criminal justice system—how it is organized, analyzed, processed, stored, and retrieved. Crime is defined as human behaviors, usually categorized as felonies,

misdemeanors, and lesser violations, for which a society provides formally sanctioned punishment. The solving of crime encompasses activities ranging from the informal discretionary disposition of complaints to the full investigation and prosecution of offenders.

This description will be used as a framework for discussing major issues regarding the police criminal investigation process. First, the types of crimes that police deal with and their general effectiveness are addressed. Second, the nature of the police-public relationship in the collection of information is examined, and the ramifications on the criminal justice system of how the police use crime information are explored. Third, how the police go about solving crime is described. Lastly, a view of future trends and issues is presented.