Former NFL player Joe McKnight was shot and killed during a road rage incident Thursday outside of New Orleans, authorities told NBC News.
The shooter, identified as 54-year-old Ronald Gasser, remained at the scene in the Mississippi River suburb of Terrytown before he was taken into custody, said Jefferson Parish Sheriff Newell Normand.
Gasser was released overnight but no charges were filed. He could not be immediately reached for comment.
The Jefferson Parish Sheriff's Office said it would consult with local prosecutors to decide whether a grand jury would be convened to review possible charges.
In the aftermath of the shooting, deputies administered CPR, but McKnight, a 28-year-old Louisiana native, "ultimately expired," Normand told reporters at the scene.
"Mr. McKnight did not have a gun in his possession," he said.
A sheriff's spokesman told NBC News that the shooting stemmed from a "road rage" confrontation but could provide no further details.
McKnight was a highly recruited New Orleans football star when he graduated from high school in 2007 and enrolled at the University of Southern California, which was just one year removed from winning the national championship.
The Trojans won 11 of their 13 games that season, including the Rose Bowl, in which McKnight ran for 125 yards on only 10 carries as USC defeated Illinois 49-17.
The rest of McKnight's college career was marred by injury and investigations of improper gifts allegedly provided to him. McKnight was banned from playing in the 2009 Emerald Bowl, and he soon went pro.
Seattle Seahawks coach Pete Carroll, McKnight's coach at USC, called McKnight's death a "terrible tragedy," saying on Twitter: "Everyone loved Joe and we are going to really miss him."
McKnight played parts of four seasons in the NFL for the New York Jets and the Kansas City Chiefs as a running back and on special teams. He was named to the Pro Bowl, the NFL's all-star game, as a kick returner after the 2011 season.
McKnight made a comeback this year in the Canadian Football League, rushing for 354 yards in seven games with the Edmonton Eskimos and the Saskatchewan Rough Riders.
The Rough Riders tweeted that it was a "sad day."