(CNN) NBA superstar LeBron James has joined the chorus of notable high-profile athletes that have voiced their outrage over the death of George Floyd.
On Monday evening, Floyd, 46, died after he told police he could not breathe as he was pinned down by an officer kneeling on his neck. Police were called about an attempted forgery in progress and Floyd was identified as a possible suspect. Floyd was arrested and pinned down after he "physically resisted," police said.
James posted an image on social media with one side showing the officer kneeling on Floyd's neck and Kaepernick kneeling on the other side with the words "This... ... Is Why" and the caption "Do you understand NOW!!??!!?? Or is it still blurred to you?? #StayWoke."
The reference to Kaepernick was over him protesting police brutality and racial injustice by kneeling during the national anthem prior to the start of NFL games while he was with the San Francisco 49ers.
Other prominent athletes that have spoken out on social media include Odell Beckham Jr., Lisa Leslie and Donovan Mitchell.
Hundreds of people took to the streets to protest in Minneapolis on Tuesday after video of the incident.
Four police officers have been fired for their involvement in Floyd's death, and Floyd's family believes that the officers should be charged with murder.
The four officers were "separated from employment," Officer Garrett Parten, a police spokesman, said Tuesday.
"I support your decisions, one hundred percent," said Mayor Jacob Frey, in a statement about police Chief Medaria Arradondo's firing of the officers. "It is the right decision for our city. The right decision for our community, it is the right decision for the Minneapolis Police Department."
The FBI is investigating the incident, and will present its findings to the United States Attorney's Office for the District of Minnesota for consideration of possible federal charges.