Keith Lamont Scott was a different person after suffering a traumatic brain injury in a motorcycle accident last year. Friends say his medications made him zone out, slurring his words and forgetting what he was saying in the middle of a conversation.

"You could look at him and tell something was wrong," said Dana Chapman, a former neighbor. "You could walk up to him, you didn't have to speak. You could look at him and tell there was a problem."

Scott was killed on Sept. 20 by a Charlotte police officer, prompting days of protests that included another man's shooting death one riotous night. Body camera and dashcam recordings released by the police department show Scott slowly backing out of an SUV. Police say he refused commands to put down a gun.

Graphic, 16-minute video released Tuesday night captures the moments just before and after the shooting, with officers treating Scott's gunshot wounds and one officer telling his colleague to "stay right here with the gun." Scott can be heard moaning as officers ask his name and one encourages him to "stay with us."

Scott's final moments also were recorded by his wife, Rakeyia, in a video shared widely on social media. She can be heard shouting to police that her husband "doesn't have a gun, he has a TBI." She pleads with the officers not to shoot before a burst of gunfire can be heard.

Police Chief Kerr Putney said officers recovered a gun Scott had in his possession, but none of the videos conclusively shows that. Scott's mother maintains he was holding a Quran.

In any case, neurologists aren't surprised that someone with a severe traumatic brain injury would be slow to react and have difficulty following instructions, particularly when orders are being shouted by police officers with their weapons drawn.

"They don't do well in stressful situations," said Dr. David Brody, professor of neurology at Washington University in St. Louis, Missouri. "They often make poor choices or impulsive decisions under stress."

Brody noted that his comments refer to severe TBIs in general, and that he never saw Scott as a patient. But he said "there's no way a patient with a TBI who doesn't know the difference between right and wrong should own a gun or drive a car."

As Scott's family prepares for his wake Wednesday and his funeral and burial Thursday in James Island, South Carolina, where his mother lives, more information about the man's condition and his life has been difficult to come by.

The family stopped talking with the media after Scott's brother-in-law, Ray Dotch, objected to questions about Scott's criminal background, saying he shouldn't have to "humanize him in order for him to be treated fairly."

"What we know and what you should know about him is that he was an American citizen who deserved better," Dotch said.

Lance Sturges, a manager at the Gastonia mall where Scott worked as a security guard last year, remembered the 43-year-old Scott as a polite man who clearly loved his seven children.

After running his motorcycle into a tree in November 2015, Scott struggled to recover from two broken hips and a broken pelvis as well as his brain injury, his mother told a TV station.

Chapman, who often works on cars outside his house in Gastonia, said he would see Scott walking twice a day, leaning on a wooden cane for support. "He had to learn how to talk again, how to walk again," Chapman said.

The two men had bonded over a love of cars, but they didn't talk much after the accident, and then Scott moved, Chapman said.

About an hour before he was killed, Scott called another neighbor, he said. They listened to his voicemail after his death, and Chapman said he was clearly distressed: "You can hear it in his voice. He literally cannot talk," Chapman said.

Another neighbor, Anthony Spain, said Scott must have zoned out as police were yelling at him.

"He was like a baby," Spain told the Gaston Gazette, comparing his friend to an Alzheimer's patient. "They killed a baby."

TBIs range in their severity. But if Scott had to relearn how to walk and talk, he likely suffered an injury acute enough to permanently affect brain function, according to Jeffrey S. Kutcher, national Director of the Sports Neurology Clinic at the CORE Institute, in Brighton, Michigan. That "can lead to devastating changes in behavior, impulse control and really, any cognitive function."

"Not having an appropriate response in a stressful, chaotic event is certainly a potential effect of a TBI," added Kutcher, director of the NBA's concussion program. Kutcher, who also never treated Scott, said the "zoning-out" Scott's friends described could be a direct effect of the TBI or medications.

Scott had several convictions and served time in prison, court records show. As a teenager, he pleaded guilty to contributing to the delinquency of a minor and received a 12-month suspended sentence. He later served six years in Texas for evading arrest with a vehicle and aggravated assault with a deadly weapon, and was released in 2011.

Court documents also show Scott's wife filed a restraining order a month before his accident, when she said he threatened to kill her and her son with a gun and hit the boy with his fist. Rakeyia Scott warned law officers then to be aware that he "carries a 9mm black" gun, and checked boxes to indicate her husband had neither a county-issued permit to buy a handgun nor a state permit to carry a concealed handgun.

"He said he is a 'killer' and we should know that," she said. But he had already left the state when deputies went to serve the restraining order two days later, and about a week after that, Rakeyia Scott dropped her request, saying "He is no longer a threat to me and my family."

The events surrounding Scott's death are more important than anything in his past, said Justin Bamberg, the family's attorney. "In the end, it was his life to live until law enforcement determined they should take it from him."