In an official statement from the Jazz, Keisel's punishment was determined after an investigation using video evidence and eyewitness accounts from others in the area:
Eric Woodyard of the Deseret News posted video of Westbrook yelling "I'll f--k you up. You and your wife" toward Keisel (warning: post contains profanity):
Westbrook told reporters after the game he heard Keisel directing racist comments toward him:
However, Keisel said he told Westbrook to "sit down and ice your knees, bro."
Per NBA.com, members of the arena security team issued multiple conduct warning cards to fans in the area where Keisel was sitting.
Westbrook also had a run-in with Jazz fans during last year's first-round playoff series. He slapped at the hand of a man who was filming him walking to the locker room after Oklahoma City's Game 6 loss.
Unless the Jazz and Thunder meet in the playoffs, they won't play again this season.