Tom Brady joined LeBron James and a host of other sports stars from the United States in calling for a federal investigation into the fatal shooting of Ahmaud Arbery.
In February, Arbery was killed while out jogging through a residential area of Brunswick, Georgia in broad daylight.
Father and son Gregory and Travis McMichael were arrested and charged with murder on Thursday after mobile phone footage of the 25-year-old's death emerged. Gregory McMichael used to work for the local police department.
Brady was one of the players to sign a letter by the NFL Players Coalition, which was sent to US Attorney General William Barr.
The letter called for action in order to restore a measure of faith in America's justice system – citing the local investigation and a failure until this week to arrest or charge the McMichaels as problematic.
"We must strive to achieve the lofty but basic promise of equal justice, a promise on which our democracy depends," the letter read.
"Having the DOJ [Department of Justice] intervene in this case and lead the investigation immediately will help us move toward that goal.
"If it does not, but instead choses to turn its back on this obvious injustice, the DOJ will relinquish its role as the champion for the defenceless and send the unmistakable message that the federal government will not protect us from violence, prejudice and injustice in our communities."
Brady's former New England Patriots team-mate Julian Edelman and Golden State Warriors coach Steve Kerr were also among the 64 signatories.
On Twitter, James expressed his indignation over Arbery's death.
He wrote: "We're literally hunted EVERYDAY/EVERYTIME we step foot outside the comfort of our homes! Can't even go for a damn jog man!
"Like WTF man are you kidding me?!?!?!?!?!? No man fr [for real] ARE YOU KIDDING ME!!!!!
"I'm sorry Ahmaud (Rest In Paradise) and my prayers and blessings sent to the heavens above to your family!! #StayWoke #ProfiledCauseWeAreSimplyBlack"
Democratic presidential candidate Joe Biden also called for justice, saying the video showed Arbery was "killed in cold blood".