Why it's called the Massacre River

My husband is still hoping for a mission trip to Haiti this year--now probably postponed to April. The Massacre River separates Haiti and the Dominican Republic. Why the unusual name? In today's letter, Pam Mann, a missionary/teacher in Ouanaminthe from Upper Arlington Lutheran Church writes:

". . . Why the river's name was changed to Massacre. Before the arrival of Christopher Columbus, the indigenous Taino and Arawak people called the river Guatapana. However, in 1936, the centuries-old name was changed. Dominican Dictator Trujillo ordered the genocide of all blacks living in the DR who could not pronounce the Spanish verb, pereir, “to perish”. Spanish r's are tricky for Haitians as are English r's. In a few days time, an estimated 25,000 were slaughtered by machete, knives or bullets. Haitians fleeing to their homeland were tracked down and butchered by machetes when the bullets ran out. The waters of the Guatapana River ran red with Haitian blood and a horrified nation renamed it.