JM 9-61.114
When Federal prosecution is declined for an individual Dyer Act violation, the Assistant United States Attorney making such decision shall notify the investigative agency of such decision and the reasons therefor. The Assistant United States Attorney shall also advise the investigative agency if "exceptional circumstances" were present in the matter. See JM 9-61.112. In addition, the Assistant United States Attorney shall remind the investigative agency of the provisions of 18 U.S.C. § 5001, if such may be applicable. The Assistant United States Attorney shall request the investigating agency to notify the appropriate local authorities, including the appropriate local prosecutive office where a prosecutable case may be present, of his or her prosecutive determination, and shall request, in those situations involving exceptional circumstances, to be notified by the investigative agency as to what prosecutive action is being undertaken by the local authorities. If the local authorities do not prosecute a matter involving exceptional circumstances, the investigative agency shall so notify the Federal prosecutor. Upon receipt of such notification the United States Attorney should review the matter in accordance with these guidelines, the present caseload of his or her office, the availability of witnesses and the sufficiency of the evidence, and the agreements and understandings reached as a result of the Law Enforcement Coordinating Committee for his or her District to determine whether Federal prosecution is warranted.
[cited in JM 9-61.710]