Video shows black man Alton Sterling being shot dead by police

Hundreds of mourners gathered in Baton Rouge for a second night of protest, prayer and remembrance for Alton Sterling whose death at the hands of police officers was caught on video.

A crowd gathers at the scene of a shooting of a man involving a St Anthony Police officer on Wednesday, July 6, 2016, in Falcon Heights, Minn. Picture: AP

Sterling, 37, was shot on Tuesday as he wrestled with two white police officers outside the convenience store where he sold music and films on compact discs. Police say he was armed.

Mobile phone video of the shooting posted online by a community activist set off angry protests, coming at a time when law enforcement officers across the country are under close scrutiny over what some see as indiscriminate use of deadly force against blacks.

On Wednesday, a Minnesota officer shot a black man in a car with a woman and a child, and authorities are looking into whether the aftermath of the killing was livestreamed in a widely shared Facebook video.

Moving quickly to keep tensions from boiling over in Louisiana, Democratic governor John Bel Edwards asked the US Justice Department to lead a civil rights investigation into the killing. “I have very serious concerns. The video is disturbing, to say the least,” the governor said.

Terrance Carter, Sterling’s 28-year-old nephew said the police, went too far. “They did it wrong,” he said. “They could have handled it better than they did. They didn’t have to shoot him!”

However, he said the family was not condoning violent protests. “The family just wants it to be peaceful. I understand right now it’s bigger than us, but at the same time we’re just trying to work through this and be smooth with it.”

Democratic presidential candidate Hillary Clinton called the shooting a tragedy and said trust between police and the communities they serve needs to be rebuilt.

“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 colour of their skin,” she said.

A law enforcement official said a gun was taken from Sterling after he was killed. It was not clear from the murky cellphone footage whether Sterling had the gun in his hand or was reaching for it when he was shot. A witness said he saw police pull a gun from Sterling’s pocket after the shooting.

Baton Rouge Police Chief Carl Dabadie jnr said Sterling was armed – he didn’t specify the type of weapon – but that there are still questions about what happened.

“Like you, there is a lot that we do not understand. And at this point, like you, I am demanding answers,” Mr Dabadie said, calling the shooting a “horrible tragedy.”

Mr Sterling was confronted by police after an anonymous caller reported being threatened by someone with gun outside the store, authorities said.

In mobile phone video, one of the officers tackled Sterling, and the two officers pinned him to the pavement.

Someone yelled, “He’s got a gun! Gun!” and one officer pulled his weapon from his holster. After some shouting, what sounded like a gunshot could be heard. The camera pulled away before more shots were heard.

The officers, identified as Blane Salamoni, who has been on the force for four years, and Howie Lake II, a policeman for three years, were placed on administrative leave, standard department procedure.