Lyndon Johnson actually said...
I hereby designate the Attorney General of the United States, and such other officers and employees of the Executive Branch of the Government as he may from time to time specify, to be the 'local authorities' and 'competent officers' on the part of the United States within the meaning of Article XIII of the Convention.
Context
Executive Order 11300—Relating to the Implementation of the Convention Between the United States and Greece
08/16/1966