The investigative report is an impartial documentation of all relevant evidence, findings, and common knowledge of the important facts surrounding a case, which may be used to lead to conclusions formed from the implications throughout the investigation. In essence, the investigative report is the definitive and permanent record of an investigation. As such, the report must be written in a way that the information is stated logically and accurate so that the reader can make an objective reasoning of the information being presented. Whether in criminal or civil cases, investigative reports may have numerous applications, given the proper audience. Generally speaking, an investigative report is the basic source of information. It may be used to provide statistical information, evaluation of the case, and documentation of different types of incidents. For example, cases involving (name some examples here). Also, depending on the audience, the investigative report may be used as a resource to newspapers and the media. Moreover, the investigative report becomes essential for the documentation of events. Some personnel at the receiving end of the report may include law enforcement agents, detectives, supervisors, prosecuting attorneys and/or the defense attorneys. If the information presented in an investigative report is accurate and factual, then these persons will be able to make more informed decisions regarding criminal charges. Also, they may use these reports for future criminal investigations, linking related crimes or other activity, and assisting officers in recalling facts before testifying in front of a judge in court.
http://www.cdpr.ca.gov/docs/enforce/compend/vol_5/chap4.pdf