Trujillo, determined to expand his influence over all of Hispaniola, in October 1937 ordered the indiscriminate butchery by the Dominican army of an estimated 15,000 to 20,000 Haitians on the Dominican side of the Massacre River.
Although conspiracies--both real and imagined--against his rule preoccupied Trujillo throughout his reign, it was his adventurous foreign policy that drew the ire of other governments and led directly to his downfall. Paradoxically, his most heinous action in this arena cost him the least in terms of influence and support. In October 1937, Trujillo ordered the massacre of Haitians living in the Dominican Republic in retaliation for the discovery and execution by the Haitian government of his most valued covert agents in that country. The Dominican army slaughtered as many as 20,000 largely unarmed men, women, and children, mostly in border areas, but also in the western Cibao. News of the atrocity filtered out of the country slowly; when it reached the previously supportive administration of President Franklin D. Roosevelt in the United States, Secretary of State Cordell Hull demanded internationally mediated negotiations for a settlement and indemnity. Trujillo finally agreed. The negotiations, however, fixed a ludicrously low indemnity of US$750,000, which was later reduced to US$525,000 by agreement between the two governments. Although the affair damaged Trujillo's international image, it did not result in any direct efforts by the United States or by other countries to force him from power.