2. The Investigation Election fraud investigations fall into two stages: a preliminary investigation, followed by a grand jury investigation along with an FBI full-field investigation. Preliminary investigations are usually initiated by the United States Attorney’s Office or FBI office that received the complaint. Consultation with the Public Integrity Section is required before grand jury and FBI full-field investigations are initiated. FBI participation must also be approved by FBI Headquarters. (a) Preliminary investigation A preliminary investigation typically involves interviewing the complainant, then conducting a sufficient investigation to: • identify the crime allegedly committed; • determine whether that crime is prosecutable under federal law; • evaluate the need for federal intervention as a function of –  the extent to which the crime may have impacted adversely on a federal election,  the extent to which the crime corrupted the registration or voting process, and  the desire and capability of local law enforcement officials to handle the case; • identify persons who may have participated in the scheme; and 92