Regardless of whether federal process is outstanding or anticipated, agents of the Federal Bureau of Investigation have authority to investigate fugitive felons when there is a reasonable basis to believe that doing so will detect or prevent the commission of a federal crime.
U.S. Marshals, including FBI agents serving as Special Deputy U.S. Marshals, have authority under 28 U.S.C. § 566(e)(1)(B) to investigate and pursue fugitives wanted under state felony warrants whenever such action is undertaken pursuant to a special apprehension program approved by the Attorney General.
Where a U.S. Marshal or Special Deputy U.S. Marshal is engaged in an approved investigation of state law fugitives under section 566(e)(1)(B), the marshal’s derivative state sheriff powers under 28 U.S.C. § 564 and the marshal’s inherent authority to take enforcement actions necessary to carry out his federal duties provide valid grounds for the marshal to arrest such fugitives.