BATON ROUGE, La. -- The graphic video shows a deadly encounter outside a convenience store.
Two police officers pin down Alton Sterling, a 37-year-old black man, then shoot him as he lies on the ground.
The video, shared widely on social media, quickly sparked local protests and drew national attention.
Baton Rouge police say they came to the scene early Tuesday after an anonymous 911 caller reported a man threatening him with a gun.
Accounts of what happened next depend on whom you ask.
Sterling is dead. Federal authorities are investigating. And the president of the NAACP's local branch is calling for the city's police chief and mayor to resign.
The U.S. Justice Department's Civil Rights Division will be the lead agency investigating the shooting, Louisiana Gov. John Bel Edwards said Wednesday. The U.S. attorney's office in Baton Rouge, the FBI and state police also will be involved, he said.
The governor, who called for calm and unity, said he has "very serious concerns" after watching the cell phone video of the shooting.
"The video is disturbing to say the least," Edwards said.
Edmond Jordan, an attorney representing Sterling's family, said the video of the shooting raises troubling questions.
"I think that the city is going to have to give us some good answers," said Jordan, who is also a Louisiana state legislator. "And I don't know if they'll be able to."
Sterling's family, he said, has seen the video of the shooting.
"(They) are taking it hard right now ... overwhelmed with grief," he said.
The 48-second video appears to be cell phone footage recorded by a witness inside a nearby car.
It begins with the camera facing a car dashboard. A single pop is heard. Then someone yells, "Get on the ground."
Another pop follows.
The camera then pans up to two officers confronting a man in a red shirt. The man is Sterling, according to his family's attorney.
An officer pulls him over the hood of a silver car and pins him to the ground. Once he's down, the officer begins to assist a second officer in restraining Sterling.
Seconds later, someone shouts, "He's got a gun."
An officer can be seen drawing something from his waist and pointing it at the man on the ground. More yelling follows, though it's hard to make out what's being said. Then there are two more bangs.
The witnesses inside the car shout and swear. Three more bangs go off. A woman in the car starts crying.
Are there other videos?
Police turned over the investigation of the shooting to the U.S. Attorney's Office and the FBI.
"It is our goal and our mission to make sure that a thorough, just, transparent and independent investigation be conducted into this incident," Police Chief Carl Dabadie Jr. said.
Dabadie vowed authorities would conduct a transparent and independent investigation into the shooting.
"Like you, there is a lot that we do not understand, and at this point, like you, I am demanding answers," he said. "Like you all, my prayers are with this community, and especially with the family and loved ones of Mr. Sterling, and all the members of the Baton Rouge Police Department."
Police officials say the video was not sent to the department but was released to the media and posted online. Police have said the officers involved have been placed on administrative leave, a standard practice following an officer-involved shooting.
The owner of the convenience store where Sterling was killed said he's sure the shooting was caught on his store's surveillance cameras, though he hasn't seen it. Police took the video later Tuesday, he said.
What about body cameras?
State Rep. C. Denise Marcelle, who said the police chief briefed her, told WAFB-TV that the officers were wearing body cameras, but the cameras fell off during the struggle and did not capture the shooting.
Jordan, the family attorney, also said he has heard the officers' body cameras fell off in the struggle.
'He was handled unjustly'
At a news conference Wednesday, the president of the NAACP's branch in Baton Rouge called for the city's police chief and mayor to resign in the wake of the shooting.
"We're actually here today to speak to the culture of the Baton Rouge Police Department. This incident is only one incident in many," Michael McClanahan told reporters. "What we're going to do is root out the 1 percent of bad police officers that go around being the judge, the jury and executioner of innocent people, period, but more specifically, innocent black lives."
The officers involved should be held accountable, McClanahan said.
"I'm calling on anybody in this city with any backbone to go and arrest those two officers," he said. "If the system will work for anybody, let it work for them, too."
Quinyetta McMillon, the mother of one of Sterling's children, teared up as she discussed the shooting video. Her 15-year-old son stood beside her, sobbing.
"The individuals involved in his murder took away a man with children who depended upon their daddy on a daily basis. ... As this video has been shared across the world, you will see with your own eyes how he was handled unjustly and killed without regard for the lives that he helped raise," she said.
McMillon vowed to join fellow citizens of Baton Rouge in making sure those responsible are held accountable.
"I, for one, will not rest," she said, "and will not allow ya'll to sweep him in the dirt."
Louisiana's governor said he expressed his condolences Wednesday to Sterling's family, speaking on the phone with his aunt. He said officials agreed there should be an independent investigation.
"There should be no doubt in anybody's mind that this incident is going to be investigated impartially and thoroughly," Edwards said.
Cause of death: 'Multiple gunshot wounds'
A preliminary autopsy found Sterling's cause of death was from "multiple gunshot wounds to the chest and back," East Baton Rouge Parish Coroner William "Beau" Clark told CNN on Wednesday.
He declined to provide additional details about how many gunshot wounds Sterling sustained.
A full autopsy will be completed over the next 60 to 90 days, Clark said, pending toxicology results.
The report then will be handed over to law enforcement, he said.
'We ain't running from this'
Protesters took to the streets in Baton Rouge near where Sterling was killed after news of his death spread.
Members of Sterling's family were among them, Jordan told CNN.
"Pretty much everybody who knows him knows he's a sweet person," his sister, Mignon Chambers, told CNN affiliate WVLA-TV.
"It wasn't right, and something needs to be done."
The protests were largely peaceful, according to local media.
Some streets were shut down, a few individuals spoke and those on the scene mostly played music and chanted.
"We ain't running from this," one man could be heard telling the crowd. "We gonna pray first, but we gonna stand tonight. We gonna stand tomorrow. And we gonna stand as a community."