The Art of Her Deal: The Untold Story of Melania Trump by Mary Jordan:
Viktor sometimes ended up with Trump’s cast-off clothing. “They’re the same size and everything,” Morales said. One day in 2013, Amalija found a red hat in a pile where Trump had placed some items that he no longer wanted to wear. She thought Viktor could use it, so she picked it up and gave it to her husband. Viktor put it on one morning and wore it to the golf course, where he ran into Trump.
Employees knew that Trump had an unwritten rule that only he could wear his distinctive red caps—making him unmistakable anywhere on the property. When he saw Melania’s father in the cap, he became furious and demanded that he take it off and leave. The caddies and housekeepers who saw this scene unfold said it was an unforgettable moment. “Nobody could wear the red hat but [Trump],” Diaz said. “The whole world saw what Trump had done to his father-in-law,” Morales added. Viktor “was very embarrassed.” Diaz said that Viktor came back to the house and screamed about “that fucking guy.” Diaz said Melania’s mother tried to calm her husband down, but recalled that Melania remained silent.