Rayshard Brooks, shot while running from police, didn't have to die, his family says.
The mayor of Atlanta agrees. On Monday, she called Brooks' death a murder.
Experts say the confrontation with police on Friday night could have been handled differently.
The family and the city are waiting to see whether the district attorney will file charges against the officer who fired three shots at Brooks and another officer who had been trying to arrest the 27-year-old man in the parking lot of a Wendy's.
Fulton County District Attorney Paul Howard told CNN's Anderson Cooper on Monday night that it comes down to what Brooks was doing when now-fired officer Garrett Rolfe pulled the trigger.
"The critical point that we are examining and the critical point I believe in this case is what happened at the exact moment of the shooting," Howard said.
If Rolfe shot Brooks, who was unarmed when searched but had taken a Taser from one of the officers, for any reason other than he was a deadly threat to others, then "it is not justified," Howard said.
The DA said there would be an announcement Wednesday on possible charges, which could range from murder to voluntary manslaughter.
Howard told CNN that from what he had seen between officers and Brooks on body cameras and surveillance video that it was difficult to understand why Brooks, who had fallen asleep at the wheel of his car and failed a field sobriety test, ended up dead.
The other officer at the scene, Devin Brosnan, is on administrative duty. He could also face charges, Howard said.
Brooks' widow, Tomika Miller, told CNN's Natasha Chen that she hadn't felt like watching the videos yet but her husband should be alive.
"I wouldn't have used a gun," against someone who had a Taser, she said. She thinks the officers should have tried to catch him and tackle him, or let him get go. "I don't think it was necessary to shoot."
By midday Monday, protesters had flooded streets in downtown Atlanta decrying Brooks' death and demanding an end to systemic racism.
They also called for an end to Georgia's stand-your-ground law and citizen's arrest law, which made national headlines after the death of Ahmaud Arbery, an unarmed black man killed while jogging in southeast Georgia.
Atlanta mayor orders changes in use of force
Mayor Keisha Lance Bottoms said the city had formed a task force last week to come up with use of force policy changes. They were to have two weeks to compile a report.
But then Brooks was shot twice in the back.
"On Friday evening, we saw the murder of Rayshard Brooks. And, as I've said before, I am often reminded of the words of Dr. Martin Luther King Jr. There is a fierce urgency of now in our communities," she said at a Monday news conference.
After deciding that she cannot wait for the task force to give her recommendations, she signed several orders calling for the city's chief executive to work with the interim police chief on changes.
Officers should use only the amount of objectively reasonable force necessary to protect themselves or others, she said. Deescalation attempts should be taken before the use of force, and the department should require officers to intervene when they see a use of force violation and report it to an on-duty supervisor.
"Our police officers are to be guardians, and not warriors within our communities," Bottoms said.
The task force is still working and should send its initial recommendations by June 24, Bottoms said.
What should the officer have done?
The fact that Brooks did not have a deadly weapon is important, CNN law enforcement analyst Charles Ramsey said. Early in the encounter, an officer asked Brooks if he could pat him down, and Brooks agreed.
"Now you know he's not in possession of a firearm or any other deadly weapon," said Ramsey, a former Philadelphia police commissioner.
After Brooks stole the officer's Taser and ran away, "it looks like he may have even fired the Taser at some point in time," Ramsey said.
But it's unlikely Brooks would have been able to use the Taser a second time, Ramsey said.
"Once you fire the Taser, it has to recycle before it can be used again," he said. "I would doubt very seriously if most citizens would even know how to operate a Taser."
So instead of shooting Brooks, Ramsey said the officer could have continued the foot pursuit, "get on a radio and call for some assistance."
"You've got the car. You've asked for his driver's license. You know who he is. So even if you don't get him right now, you can get him later," Ramsey said.
"The need to immediately apprehend is taken away. And you can only use deadly force under certain, very narrow circumstances," such as if the officer's life or anyone else's life is in danger, or if the person being pursued poses a serious danger to the public.
"That's not the case here," Ramsey said.
Family calls for changes
Rayshard Brooks' relatives spent the last several weeks following nationwide protests against police brutality.
But they never expected the young father be the next black man to die at the hands of police.
"On June 12, one of our biggest fears became our reality," his niece Chassidy Evans said. "Not only did we lose another black, unarmed male. This time it landed on our front doorstep."
"Not only are we hurt, we are angry. When does this stop? We're not only pleading for justice. We're pleading for change."
Brooks' cousin Tiara Brooks said excessive force must stop.
"How many more protests will it take to ensure that the next victim isn't your cousin, your brother, your uncle, your nephew, your friend or your companion so that we can finally end the suffering of excessive police force?" she asked, fighting back tears.
‘Destroying things is not going to help'
Brooks' family thanked all the protesters who are peacefully demanding an end to excessive police force.
"I'm not only asking for the city of Atlanta to stand with us. I'm asking for everyone in this nation to stand with us as we seek justice for Rayshard," said Evans, the niece of Brooks.
While rallies Monday have been peaceful, police are still looking for whoever set fire Saturday night to the Wendy's where Brooks was killed. Police are offering a reward of up to $10,000 for information leading to the arrest of the arsonist.
Brooks' widow said protesters must remain peaceful. Otherwise, their message is lost.
"I want them to keep protesting, keep fighting. But destroying things is not going to help at all. Destroying things is going to make us look like savages ... I may as well burn my own house down," Miller said. "Let your time not be wasted."