LeBron James, Colin Kaepernick among athletes speaking out on George Floyd's death

LeBron James and other high-profile athletes have taken to social media to voice their outrage over the death of a black Minnesota man who was pinned down by police.

George Floyd, 46, died Monday night while in Minneapolis police custody. A bystander's video showed an officer kneeling on the handcuffed Floyd's neck, even after he pleaded that he could not breathe and stopped moving.

James weighed in Tuesday night on Instagram with a post referencing Colin Kaepernick, the NFL quarterback who famously kneeled during the national anthem to protest police brutality and racial injustice.

James' post includes a photo of the officer kneeling on Floyd's neck alongside a photo of Kaepernick kneeling during the anthem, topped with the caption: "This ... ... Is Why." The Los Angeles Lakers star wrote in the post: "Do you understand NOW!!??!!?? Or is it still blurred to you?? #StayWoke"

James has been vocal about social issues such as police brutality throughout his career. He also posted an Instagram story Tuesday that included a photo and video of Floyd's arrest along with the caption: "We're hunted."

Former NBA player Stephen Jackson was friends with Floyd and has shared a number of social media posts about his death. Jackson, who previously worked as an ESPN analyst, called Floyd by the nickname "Twin" and noted that "both of our names will live forever."

The Minnesota Vikings said they were deeply saddened by the incident, which happened just blocks away from their U.S. Bank Stadium.

"Everyone in our community deserves the right to feel protected and safe," the team tweeted.

NFL stars Odell Beckham Jr. and DeMarcus Lawrence, NBA stars Jaylen Brown and Donovan Mitchell, and Basketball Hall of Famer Lisa Leslie also tweeted their frustration over Floyd's death.

Kaepernick also shared on his Instagram stories the split image of the officer kneeling on Floyd's neck and Kaepernick kneeling during the national anthem. His post came from a tweet made by former NFL wide receiver Nathan Palmer.

Formula One star Lewis Hamilton shared James' post on his Instagram stories.

Houston Texans defensive end J.J. Watt called Floyd's death "disgusting" and "upsetting" during a news conference Wednesday.

"I've seen the video, and I think it's disgusting," Watt said. "I think that there's no explanation. I mean, to me, it doesn't make any sense. I just don't see how a man in handcuffs on the ground, who is clearly detained and clearly saying, in distress ... I don't understand how that situation can't be remedied in a way that doesn't end in his death. I think that it needs to be addressed. Strongly, obviously."

Four Minneapolis officers involved in Floyd's arrest were fired Tuesday after video of the incident gained national attention. Mayor Jacob Frey announced the firings on Twitter, saying, "This is the right call."

Floyd's death is under investigation by the FBI and state law enforcement authorities. It immediately drew comparisons to the case of Eric Garner, an unarmed black man who died in 2014 in New York after he was placed in a choke hold by police and pleaded for his life, saying he could not breathe.

After Garner's death, James, Kyrie Irving and Derrick Rose were among the players to wear "I Can't Breathe" T-shirts during pregame warm-ups as a display of protest and to show support for Garner's family.

Protesters in Minneapolis on Tuesday night filled the intersection where Floyd was arrested. They eventually marched about 2½ miles to a city police precinct, with some protesters damaging windows and a squad car and spraying graffiti on the building.

The Associated Press contributed to this report.