President Donald Trump this week angrily insisted that he's "never used racist remarks" to describe people of color -- but a man who's known him for years says otherwise.

Jack O'Donnell, the former president of Trump Plaza Hotel & Casino, has written a column for Politico that calls B.S. on Trump's claim to have never disparaged minorities with racial slurs.

"I know the real Trump better than most," O'Donnell writes in his editorial. "For three-and-a-half years, I worked in almost daily contact with him at the highest levels of the Atlantic City casino empire over which he once held sway. I saw him treat black people and minorities as inferior."

O'Donnell claims that he regularly chided the future president for his racist remarks -- but Trump continued making them anyway.

O'Donnell also says that Trump would express annoyance when he believed there were too many black customers gambling at his casinos.

"I recall one busy Saturday night, walking the casino floor with him, when he saw what he considered an inordinate number of black customers," O'Donnell recalls. "'It's looking a little dark in here,' he calmly stated. It was his way of telling me to limit our charter bus programs in urban neighborhoods. I ignored him and continued to run the business in the best interest of Donald, the bondholders and the employees."

O'Donnell says that Trump would regularly use ethnic identity to insult people who have upset him, including a limo driver who angered him by wearing clothes that Trump said made him look "like a f*cking Puerto Rican."

Read the whole editorial here.