Criminal investigation units offer invaluable support to the police in solving crimes and bringing perpetrators to justice. A police criminal intelligence investigator is a trained and experienced officer who specializes in investigating, solving and prosecuting serious crimes such as narcotics, racketeering, fraud or homicide. Unlike uniformed police officers, criminal investigators do not wear uniform to be more effective in their intelligence gathering duties, which sometimes involve going undercover among suspected groups.
A criminal intelligence investigator follows up on crimes reported to the police department. Uniformed police prepare initial reports on crimes they witness while on patrol or those that civilians report at the station. The matter is then assigned to a criminal investigator, either because it is his area of expertise or because he is on call. He follows up on the report by preparing and executing an investigation plan that involves interviewing witnesses, suspects and victims, positively identifying suspects through physical evidence such as fingerprint verification and examining all available leads.
Criminal investigators gather intelligence to discover the facts of a case and solve the crime. The police investigator visits the scene of the crime and secures any evidence that may lead towards identifying the perpetrators. An investigator will collect any physical evidence found at the scene of the crime including fingerprints and DNA and carefully study any clues such as blood spatter patterns, footprints, the position of items found on the scene and so forth. However, there are times when there is no physical evidence, and the investigator has narrowed it down to a specific suspect, so it becomes necessary to conduct undercover work. Criminal investigators also conduct surveillance and cultivate sources and informants who aid them in gathering intelligence.
Criminal intelligence units, through the contributions of their investigators, develop comprehensive databases that allow for the analysis and dissemination of information that is vital to investigations. For example, the Automated Fingerprint Identification System is a database compiled and updated by criminal investigative units nationwide to identify suspects correctly through their fingerprints. Other databases contain information about gun ownership and registration, sex offenders, psychological profiles of offenders and even international criminals. A criminal investigator will research and analyze the information in the databases to investigate a crime and in some instances prevent one where he identifies a trend.
A police criminal intelligence investigator prepares a case for court using thorough investigation, proper handling of suspects and meticulous collection of evidence. The investigator prepares witness statements and secures the attendance of witnesses at trial. He also ensures proper storage of evidence in the police lockers and ascertains that the chain of evidence is intact so that it is useful for proving the facts of the case during the hearing. A criminal investigator might also have to testify in court and he needs to be familiar with the facts of the case and the relevant law to avoid losing the case and letting the perpetrators go free because of a technicality.