In early 1932, a letter Rhoads had written in November 1931, which disparaged Puerto Ricans and makes claims (which he referred to later as jokes) he had intentionally injected cancer cells into his patients, was given by a lab assistant to Puerto Rican nationalist leader Pedro Albizu Campos. He publicized the letter in the Puerto Rican and American media, which led to a scandal, an official investigation, and a US whitewashing campaign to protect Rhoads and, by extension, Rockefeller interests. In the ensuing investigation, Rhoads defended himself, saying he had written his comments in anger and as a joke to a New York colleague. Neither Puerto Rico's Attorney General nor the medical community found evidence of his or the project's giving any inappropriate medical treatment, and the scandal was forgotten.