Investigations of criminal offenses are actions that reveal, collect and expose information about a probable criminal offense for which he / she is prosecuted ex officio, his perpetrator and other circumstances relevant to the initiation of criminal proceedings. The criminal complaint was a written or otherwise communicated notification of the criminal offense prosecuted ex officio, addressed to the state attorney. Criminal investigation is a set of police powers, measures and actions taken when there is a basis for suspicion of being prepared or committed a criminal offense or a misdemeanor, or there is a suspicion that a particular phenomenon threatens or could endanger human lives, their rights, freedom, security, inviolability or property to detect a criminal offense or misdemeanor, find perpetrators, prevent the perpetrator from hiding or escaping, to detect or provide traces and objects that may serve to determine the facts and to collect information that may be of use for the successful conduct of a criminal or misdemeanor procedure. Investigations of criminal offenses are prosecuted by a police or state attorney, and most often this is done by the police according to the order and instructions of the state attorney.