In October 1973, the Justice Department filed this civil rights case in the U.S. District Court for the Eastern District of New York (federal court in Brooklyn) against Fred Trump, Donald Trump, and their real estate company. The complaint alleged that the firm had committed systemic violations of the Fair Housing Act of 1968 in their many complexes--39 buildings, between them containing over 14,000 apartments. The allegations included evidence from black and white "testers" who had sought to rent apartments; the white testers were told of vacancies; the black testers were not, or were steered to apartment complexes with a higher proportion of racial minorities. The complaint also alleged that Trump employees had placed codes next to housing applicant names to indicate if they were black.
If you really knew Trump's racist history, you wouldn't ask for proof.