The 911 call that brought police to a Baton Rouge convenience store Tuesday came from a homeless man, according to a senior law enforcement official. The homeless man had approached Alton Sterling, repeatedly asking him for money, the official said. Sterling showed his gun and the homeless man called police, according to the official. Sterling was later shot by police at the scene.
BATON ROUGE -- Just 24 hours after his death, much of the United States had heard about the death of Alton Sterling.
Figuring out what led up to those fateful seconds -- and what the repercussions, if any, will be -- will take much longer.
Federal authorities have taken charge of the investigation into the Tuesday killing of Sterling, a 37-year-old black man who sold CDs and DVDs outside the Triple S Food Mart in Baton Rouge, Louisiana.
Sterling was shot outside the store after an encounter with two police officers. The officers could be seen in video on top of him before the shots were fired.
Protests began Tuesday afternoon in Baton Rouge and were largely peaceful. Vigils and memorials have spread across the country.
Local civic leaders and Sterling's loved ones have promised to continue their push to find the truth.
"I, for one, will not rest," Quinyetta McMillon, the mother of one of Sterling's children, said Wednesday, "and will not allow y'all to sweep him in the dirt."
As she spoke, McMillon and Sterling's 15-year-old son stood by her side, sobbing.
The U.S. Justice Department's Civil Rights Division is leading an investigation into what happened. The U.S. attorney's office in Baton Rouge, the FBI and state police also will be involved in the investigation, Louisiana Gov. John Bel Edwards said.
One of the crucial next steps will be to determine what happened before the confrontation ensued.
Authorities said that the officers were responding to a 911 report of a man with a gun. A source close to the investigation told CNN the witness who called 911 said Sterling was "brandishing a gun."
Abdullah Muflahi, the owner of the Triple S Food Mart, told CNN he wasn't aware of any incident Tuesday that would have spurred a 911 call.
But 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 told CNN.
There also is police body camera footage of the shooting -- even though the cameras were dislodged -- Baton Rouge police Lt. Johnny Dunham told reporters. The cameras continued to record, he added.
Investigators said they'll review multiple videos of the shooting, and they're canvassing for witnesses.
Authorities haven't said what those police videos or other surveillance footage of the scene show, including the lead-up to what the public has already seen or the possible weapon-brandishing incident.
The source involved in the investigation told CNN that the other videos are not nearly as clear as the bystander videos.
There are two videos that have publicly surfaced showing Sterling's killing -- one that surfaced early Tuesday, catapulting the case into the national spotlight, and a second shorter video that is of higher quality and was recorded nearer to the shooting.
The first video posted online Tuesday night quickly sparked local protests and drew national attention.
It begins with the camera facing a car dashboard as the three men stand near the vehicle. A single pop is heard. Then someone yells, "Get on the ground."
An officer pulls Sterling 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 him.
Yelling ensues, though it's hard to make out what's being said. Then there are two bangs.
The witnesses inside the car shout and swear. Three more bangs go off. A woman in the car starts crying.
The second video shows Sterling already on the ground, on his back. One officer is kneeling to Sterling's left. The other officer appears to be straddling Sterling's legs. Sterling can be seen from the chest up and his lower legs are also visible. His left arm and hands are not visible; his right arm is by his side.
After gunshots are heard, the camera pans to the right then back to Sterling, who has a large blood stain on his chest. The officer who was on his legs now lies on the pavement above Sterling's head, his gun pointed.
The officer radios for an ambulance. As Sterling moves his left arm toward his face and then his chest, the other officer appears to remove something from one of Sterling's right pockets. Baton Rouge Police Chief Carl Dabadie Jr. said Sterling was armed at the time he was killed and one witness said the officer removed a gun from Sterling's pocket.
The officers involved in Tuesday's shooting -- Blane Salamoni and Howie Lake II -- have been placed on administrative leave. A source close to the investigation told CNN the officers were interviewed Tuesday night.
Tensions are running high in the city of 238,000 people as officials vowed to be transparent about how they handle the controversial case that has sparked vigils in cities around the country.
"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," said McMillon, the mother of Sterling's child.
Edmond Jordan, an attorney representing Sterling's family, said the first video of the shooting raises troubling questions.
"I think that the city is going to have to give us some good answers," Jordan, who is a Louisiana state legislator, told CNN. "And I don't know if they'll be able to."
The 'CD man'
Sterling was known as the "CD man," a laid-back guy who would sell tunes and DVDs outside the convenience store where he was shot, according to local media.
"Alton was a respected man. He was beloved in the community. He did not deserve the treatment and this excessive force that was exerted on him by the police department," Jordan, the Sterling family attorney, told CNN.
Muflahi said he'd known Sterling for six years and never saw a confrontation between Sterling and anyone. Sterling never got into fights, he said.
"Just five minutes before (the shooting)," Muflahi said, "he walked into the store getting something to drink, joking around, (and we were) calling each other names."
Sterling has had encounters with law enforcement before.
In 2009, he was charged with carrying a weapon (a firearm) while in possession of a controlled substance (marijuana). He pleaded guilty two years later and was sentenced to five years in prison, with credit for time served and a recommendation of work release and drug treatment. Sterling had pleaded guilty to other charges in the past.
There's no evidence that officers who responded to the convenience store early Tuesday were aware of his criminal history.
CNN's Steve Visser, Dave Alsup, Polo Sandoval, Chuck Johnston, Shawn Nottingham, Tristan Smith, Nick Valencia, Sheena Jones, Kate Conerly and Donie O'Sullivan contributed to this report.