Dwyane Wade and LeBron James were only a few miles away from Trayvon Martin on Feb. 26, participating in the NBA All-Star game on the night the unarmed black teenager wearing a hooded sweatshirt was shot to death by a neighbourhood crime-watch volunteer.

They never knew the teenager, but on Friday they decided it was time to speak out.

Wade posted a picture of himself from a photo shoot wearing a hooded sweatshirt, otherwise known as a hoodie, to his Twitter and Facebook pages on Friday morning.

A couple of hours later, James posted another photo — this one of the Heat team, all wearing hoodies, their heads bowed, their hands stuffed into their pockets. Details of when and where the photo was taken were not immediately available.

'This situation hit home for me because last Christmas, all my oldest son wanted as a gift was hoodies.'—Miami Heat star Dwyane Wade

Among the hashtags James linked to the photo: "WeWantJustice."  "As a father, this hits home," said Wade, who has two sons, aged four and 10.

Martin was killed in Sanford, Fla., as he was returning to a gated community, carrying candy and iced tea. A neighbourhood crime-watch volunteer, George Zimmerman, said he acted in self-defence and has not been arrested, though state and federal authorities are still investigating.

Protests have popped up nationwide in recent days, with thousands of people — many of them wearing hoodies — calling for action.

"This situation hit home for me because last Christmas, all my oldest son wanted as a gift was hoodies," Wade told The Associated Press Friday from Auburn Hills, Mich., where the Heat would go on to beat the Detroit Pistons 88-73. "So when I heard about this a week ago, I thought of my sons. I'm speaking up because I feel it's necessary that we get past the stereotype of young, black men and especially with our youth."

Wade and James decided Thursday to make their reactions about the Martin situation public, and James felt the best way to do that was the team photo with everyone wearing hoodies.

Several Heat players, including Wade and James, took the floor Friday night with messages such as "RIP Trayvon Martin" and "We want justice" scrawled on their sneakers.

"I couldn't imagine if my son went to a store just to get some Skittles and a pop or iced tea and they didn't come home," Heat forward Udonis Haslem said. "We've been following the story individually very closely. It's just unfortunate. We just feel like something needed to be done about it. It's only right. It's only fair. ... I think it's at least a start in the right direction."

Other tributes were going on in NBA arenas on Friday night. Carmelo Anthony tweeted a photo of himself in a gray hoodie, with the words "I am Trayvon Martin!!!!!" over the picture, and his New York Knicks' teammate Amare Stoudemire — a central Florida native — arrived for his team's game in Toronto wearing a hooded sweater. Stoudemire also wore a gray hoodie while working out long before tip-off.

On Friday, Fox News Channel commentator Geraldo Rivera said on Fox & Friends the hoodie Martin wore when he was killed was as much responsible for his death as the man who shot him. Rivera later said his comment was "politically incorrect."

Separately, a Florida state lawmaker, Representative Alan Williams, a Democrat from Tallahassee, urged the Heat stars — along with New York Knicks forward Amare Stoudemire, a central Florida native — in an early Friday post on Twitter to wear hoodies during pregame warmups to call attention to the Martin story.

Such a move would not be permitted under the NBA's uniform policy, although Heat players are planning to pay tribute to Martin in some manner when they face the Pistons on Friday night.

"When you see Trayvon, when you see that image, he could be anybody's kid, black or white, Hispanic, Asian, what have you," Williams said in a telephone interview. "Basketball is a sport that kind of transcends race and class and all those things that divide us. For me, as a state representative, we have to go beyond the traditional routes that some people would take."

The players' association called not only for Zimmerman's "prompt arrest," but a review of the Sanford Police Department.

"Their silence in the face of this injustice is reprehensible and they cannot be trusted to safe guard the citizens of the Sanford community equally," the NBPA said. "The NBPA seeks to ensure that Trayvon Martin's murder not go unpunished and the elimination of the injustices suffered by the innocent."