In late April 1919, at least 36 booby trap dynamite-filled bombs were mailed to a cross-section of prominent politicians and appointees, including the Attorney General of the United States, as well as justice officials, newspaper editors and businessmen, including John D. Rockefeller [REF].
News reports of the Hardwick bomb described its distinctive packaging; an alert post office employee in New York connected this to 16 similar packages which he had set aside a few days earlier for insufficient postage.