SALT LAKE CITY • Russell Westbrook's beef with Utah Jazz fans dates back to last April, when the Oklahoma City Thunder were eliminated from the play-offs after losing their first-round series 4-2.
He had a bust-up with a supporter, who was recording his exit down the players' tunnel, before accusing the crowd of saying "a lot of disrespectful, vulgar things".
On Monday, the guard again got into another heated exchange with the home fans during his team's 98-89 National Basketball Association (NBA) win, with the confrontation going viral on social media.
The 2017 Most Valuable Player was caught on video threatening a couple, telling them: "I swear to God. I will f*** you up...
"I promise you. On everything I love. Everything I love. I promise you."
Westbrook, who had 23 points, 11 rebounds and eight assists, issued a statement after the game, saying: "The young man and his wife in the stands told me to get down on my knees like you used to.
"For me, that is completely disrespectful. It is racial. It is inappropriate. There are people who come to the games to say mean disrespectful things about me and my family.
"For many years, I have done all the right things and never done anything to hurt or harm anybody. Never been in any trouble. Never fought a fan."
However, Jazz fan Shane Keisel, who was involved in the incident, denied he had used a racial slur, telling ESPN "he just went nuts".
He added: "She (girlfriend Jennifer Huff) never got up. She never said a word to him... no man should threaten a woman, period.
"I'm not afraid of the guy. Come on up. But when you threaten a woman... you're a big man. So this guy needs to be exposed."
But, according to Utah daily The Deseret News, Keisel was among five Jazz fans that received "warning cards" as their comments, gestures and behaviours directed at players were in violation of the league's fan code of conduct.
A Jazz spokesman said on Monday evening that "players and fans have a shared responsibility to create a safe and respectful environment", and confirmed an investigation had been launched into "the unfortunate exchange".
In Los Angeles, Lou Williams scored 34 points to become the most prolific bench scorer in league history as the Clippers continued their charge towards the play-offs with a 140-115 victory over the visiting Boston Celtics.
The hosts won their fifth straight game to move into sole possession of sixth place in the West after the guard, who leads the NBA in points off the bench this term, passed Dell Curry as the highest-scoring player off the bench of all time.
Williams now has 11,154 points as a reserve in his career, while Curry, the father of Golden State Warriors star Stephen, had 11,148.
AGENCE FRANCE-PRESSE, REUTERS