Probe launched after US police shoot and kill black man

Alton Sterling was shot by two white police officers outside a convenience store in Louisiana.

Picture: Scott Olson/Getty Images North America/AFP.

JOHANNESBURG - The United States Justice Department says it will investigate the killing of a black man by two white police officers outside a convenience store in Louisiana.

Graphic images of the shooting of Alton Sterling have stirred protests and sparked outcries on social media.

In a video, Sterling is seen pinned to the ground and shot in the chest at least four times at close range.

The footage also appears to show one of the officers removing at item from his pocket as he lay dying on the ground.

Disclaimer: Please be advised that the video footage below is not for sensitive viewers and contains some foul language:

Sterling's aunt, Sandra, says he was only trying to figure out what he did wrong.

"He was a big guy and when they tased him, on the first video I could hear him asking them: 'What did I do? You charged me with a gun and came at me with a gun, what did I do?'"

Several hundred people gathered for a prayer vigil near the spot where Sterling was killed, with speakers urging peaceful protests, justice and unity in the face of "excessive force" used by police against black residents.

"If we stand divided, we are already defeated," Bishop Gregory Cooper of Baton Rouge told the crowd, including families with children, that filled the parking lot and nearby streets. Police stayed on the fringes of the gathering.

Many people stayed hours after the service and a brass band joined a large, peaceful nighttime march circling the store. A local artist had painted a mural of Sterling on the wall just feet from where he was shot.

Officials scrambled to defuse tension, saying there would be an independent investigation, after media showed a separate graphic video of the shooting recorded by a bystander.

"I have very serious concerns. The video is disturbing, to say the least," Governor John Bel Edwards told reporters.

Baton Rouge Mayor-President, Kip Holden, and police said they welcomed the probe launched by the Justice Department, the Federal Bureau of Investigation and federal prosecutors.

Such incidents undermine trust between police and the communities they serve, said presumptive Democratic presidential nominee Hillary Clinton.

"Something is profoundly wrong when so many Americans have reason to believe that our country doesn't consider them as precious as others because of the color of their skin," she said in a statement.

There was no immediate statement from presumptive Republican nominee Donald Trump.

"HE'S GOT A GUN"

Video recorded on the bystander's cell phone shows an officer confronting Sterling and ordering him to the ground. The two officers then tackle him to the pavement, with one pulling a gun from his holster and pointing it at his chest.

Three more shots are heard, before the camera shows one officer lean over Sterling and take something from his pocket.

Police did not say how many shots were fired and declined to say whether a stun gun was used on Sterling. Muflahi said police tasered Sterling before he was tackled.

The two police officers involved, Blane Salamoni, a four-year veteran, and Howie Lake, a three-year veteran, were both put on administrative leave, Baton Rouge Police Chief, Carl Dabadie, told a news conference.

The officers were responding to a call about a black man reported to have made threats with a gun, Dabadie said.

'When officers arrived, Sterling was armed and the altercation ensued that resulted in the loss of his life," Dabadie said.

The body cameras of both officers became dislodged during the altercation, but continued recording audio and video, police said. Those and other recordings will be turned over to federal investigators, police spokesman Lieutenant Jonny Dunnam said.

RAP SHEET

Court records show Sterling had several criminal convictions since the mid-1990s, for battery, resisting arrest, burglary and other crimes. He was a registered sex offender after spending close to four years in prison for felony carnal knowledge of a juvenile.

Relatives and acquaintances described Sterling as jovial and friendly, a neighborhood fixture who had peddled copied CDs, DVDs and games in front of the Triple S Food Mart for years.

Cameron Sterling, Alton's 15-year-old son, broke down crying at a news conference as his mother spoke. "He was killed unjustly and without regard for the lives he helped raise," said the mother, who did not give her name.

Several people were arrested for blocking traffic in downtown Philadelphia during a protest over the killing, broadcaster NBC Philadelphia reported.

Additional reporting by Reuters.