A New Orleans sheriff has denied that a 54-year-old man stood over ex-NFL star Joe McKnight and shot him dead after a roadside altercation, instead saying he fired three rounds from the driver's seat of his car.

Jefferson Parish Sheriff Newell Normand dispelled a supposed eyewitness account which suggested Ronald Gasser, who has since been released without charge, had stood over McKnight yelling: 'I told you don't you f*** with me', before firing again.

Sheriff Normand said instead that Gasser fired three rounds from the driver's seat of his car with a .40-caliber weapon, through an open passenger window at McKnight, who was standing at the window.

Witnesses had heard a 'heated verbal exchange' between the two men from their cars before a 'rapid succession' of gunfire.

Three bullet casings were found in the car. An autopsy found McKnight had a wound to his hand, one to his right nipple and a third to his right shoulder which punctured a lung.

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Denial: Jefferson Parish sheriff Newell Normand insisted that Joe McKnight had been shot three times by Ronald Gasser from the driver's seat of his car through the open passenger window at McKnight, who was standing at the window. Three casings were found

Ronald Gasser, 54, (pictured after the incident) was taken into custody following the shooting. He has been released without charge

Ex-NFL star Joe McKnight was shot dead by a 54-year-old white man following an alleged road rage incident in Terrytown, New Orleans on Thursday

Suggesting that the incident in Terrytown could have been sparked by something as simple as one man 'recklessly' cutting off the other, he added there was no witness account of an apology being made by McKnight to Gasser and no video of the incident.

Acknowledging that the department been accused of dropping the ball, Sheriff Normand insisted that Gasser was released because in the state of Louisiana, 'there are some relative statutes that provide defenses to certain crimes.'

He said that the 'stand your ground' law 'looms on the horizon' but didn't discuss further. He added that Gasser was released 'out of an abundance of caution'.

'This investigation is not going to be moved, influenced, coerced or changed in any way by any external force, comments or otherwise,' he said. 'I can't control what's on the social networks, and if we want to be silly, that's fine.'

He added: 'The easiest thing for me would have been "book em, Danno,", but the fact of the matter is in trying to flesh out these details... we chose not to do that.'

The easiest thing for me would have been "book em, Danno,", but the fact of the matter is in trying to flesh out these details... we chose not to do that. Sheriff Newell Normand

Sheriff Normand insisted that the attack wasn't about race, saying no witness has thus far suggested a hate crime.

'This isn't about race. And I'll just throw this out folks so that everybody knows and there's no hiding the ball. The gentleman that raised Joe McKnight used to work for this office.'

But he threatened to arrest any protesters who threatened to shut down the Western Expressway.

The claim that Gasser had stood over McKnight, as well as his subsequent release, led to outrage from former teammates of McKnight.

Antonio Cromartie, a former Jets teammate of McKnight's, was earlier incensed by the decision to release Gasser, seizing on the false information that Gasser stood over McKnight.

'How in hell do you release someone who killed my brother, my friend a father a son a brother without charging him. Bull Crap.

The shooting in Terrytown, New Orleans, occurred at about 3pm on Thursday

McKnight's family members identified the 28-year-old who was pronounced dead at the scene

'You tell how can a man murder someone go get to sleep in his bed at night. But my brother can't. What the hell am I to tell my nephew.

'He stood over and murdered him. What else do you f***ing need New Orleans Police Department. Y'all ain't protecting and serving s***.'

Zach Brown, who plays for the Buffalo Bills, wrote: 'Wtf no charges! Y'all have the damn video! N.O. Have to change the damn gun law! This is getting outta hand now. Something have to change!!'

Kyle Williams, who used to play with McKnight at the Chiefs, wrote, wrote: 'This is some bulls***!!! He stood over him and shot him in broad daylight!!! And f***in stayed there!! Released and not charged!!?!?!?'

Shantell Dobard, 41, a relative of McKnight, said the decision had 'got me sick to my stomach'.

'I'm just disappointed how they just let him go free after he shot to death an unarmed man,' she told Nola.com. 'The system is so screwed up.'

Morris Reed, the president of the NAACP's New Orleans chapter, said: 'We think a black man was lynched yesterday. We're demanding answers.'

Incensed: Antonio Cromartie accused Glasser of murdering his former Jets teammate and was furious that the police department released him without charge; the claim that he stood over and murdered him has however been denied

Stung: Antonio Cromartie (pictured in Jets Uniform in 2012) was clearly affected by the death of McKnight, retweeting lots of tributes on Thursday before making his feelings known about the release Friday

Gasser was questioned by homicide detectives overnight. He never left the scene of the shooting and turned his gun into authorities.

When asked if Gasser had a criminal record, Sheriff Normand said there was an issue stemming from about 10 years ago, but could not remember the specifics.

He was pictured sitting by his car as medical staff attempted to revive McKnight.

Although there is no question that Gasser shot McKnight, the Sheriff said that officers were still piecing together the circumstances of the shooting.

Medical emergency staff gave the 28-year-old CPR on the street but he was pronounced dead at the scene after suffering multiple gun shot wounds, the Jefferson Parish Sheriff's Office said.

McKnight was not armed at the time, according to police.

Gasser's family said they were shocked by the incident and were struggling to understand.

'I'm speechless at the moment,' his daughter Candice Gasser-Bua said.

The alleged shooter's sister, Sharon Weileman, said: 'He's the best guy, the most generous guy. I have no idea what happened. I can't even talk right now.'

Gasser ran his own own telecommunications business, lived alone in his house and was rarely seen by his neighbors.

Neighbors said he moved into the house 15 years ago to live with his father, but he died last year.

'I never saw anyone else coming or going out of there,' a resident said, referring to Gasser as a loner.

McKnight played football for John Curtis High School and the University of Southern California. The running back was drafted by the New York Jets in 2010 and the Kansas City Chiefs in 2014.

His stepfather, Elmo Lee, said McKnight was about to be signed by the Minnesota Vikings.

'I just want people to know that this was not a troubled kid. The boy was just trying to make it back in the NFL, that's all he wanted to do,' he said.

'That was his whole dream since six years old. I've been knowing him from six, and this is just senseless, and it has to stop. Somewhere it has to stop.'

The shooting occurred at about 3pm at the intersection of Behrman Highway and Holmes Boulevard

Friends and family of former NFL player Joe McKnight gathered at the scene on Thursday

Jefferson Parish Sheriff Newell Normand consoled a woman at the scene of former NFL player Joe McKnight's homicide

McKnight had just finished a season playing for the Saskatchewan Roughriders in the Canadian Football League.

The head coach Chris Jones released a statement saying: 'We are shocked to hear the news of Joe's sudden passing. We send our deepest sympathies to Joe's family, friends, and all those impacted by this tragedy.'

Fans and former teammates posted tributes on social media following news of his shock death.

The New York Jets tweeted: 'Rest in peace, Joe McKnight. Our thoughts and condolences are with his loved ones'.

Current players including center Nick Mangold recalled him as a 'good dued. Always had a joke, make you smile. Just a really good guy.'

Cornerback Darrelle Revis said: 'Joe had a veyr energetic personality, a very cool cat. My memories from him are working hard. He came in his rookie year and it was a little rocky for him trying to learn the system.

'And then his second year he took off as an explosive kick returner and he won us numerous game. It was awesome to see him excel not only as a teammate but as a friend.'

Journalist Eric Allen tweeted: 'Back in 2011, we asked #JoeMcKnight who his best friend on the #Jets was and he said, 'Everybody's my best friend.' That was Joe.'

The New York Jets tweeted: 'Rest in peace, Joe McKnight. Our thoughts and condolences are with his loved ones' following news of his death on Thursday

Plea: Reggie Bush, who was drafted by the New Orleans Saints and like McKnight was a USC alum, said he couldn't understand at what point people were able to talk out their differences

McKnight's death comes just months after retired New Orleans Saints star Will Smith was also shot dead in New Orleans.

The 34-year-old was fatally shot in the back and side after exchanging words with the driver of a Hummer H2 that rear-ended his Mercedes G63 SUV in April.

Smith's wife was shot twice in the right leg.

New Orleans Mayor Mitch Landrieu said this week that gun violence in the city was 'out of control' after a mass shooting left nine injured and one dead on the famous Bourbon Street on Sunday morning.