The Secretary of State is not required to convene a Board in the case of an incident described in paragraph (1) that involves any facility, installation, or personnel of the Department of Defense with respect to which the Secretary has delegated operational control of overseas security functions to the Secretary of Defense pursuant to section
4805 of this title. In any such case, the Secretary of Defense shall conduct an appropriate inquiry. The Secretary of Defense shall report the findings and recommendations of such inquiry, and the action taken with respect to such recommendations, to the Secretary of State and Congress.