A county prosecutor investigating the police shooting of a black motorist in Minnesota on Friday said law enforcement authorities in his state and nationwide must improve practices and procedures to prevent future such tragedies, regardless of the outcome of his probe.

For much of the almost 10-minute video, Ms Reynolds can be heard wailing, off and on camera, as police apparently cast her phone to the side at one point and later handcuff her, so she cannot hold the mobile phone up.

Mr Dayton called for the US Department of Justice to open its own investigation, but the department said yesterday it would assist the state investigation as necessary.

The gathering was the second time a crowd had gathered outside the governor's residence after the shooting of Philando Castile by a police officer in suburban Falcon Heights.

Mark Zuckerberg has responded to a Facebook Live video that shows the aftermath of the death of Philando Castile.

Sterling was killed during an altercation with two white police officers and a video of the incident recorded by a bystander on his smartphone triggered outcry on social media.

By now coast to coast (perhaps the world) as been shaken with emotions after the Police Shootings of Alton Sterling in Louisiana and Philando Castile in Minnesota - both just days after we Celebrated Independence Day as a Nation United Under God.

"The police officer stopped us for a busted taillight that wasn't busted", she said, adding they were calmly following the officer's instructions.

Reynolds' video showed Yanez outside the vehicle pointing a gun inward. "Exercising our right to bear arms should not translate to a death sentence over something so trivial as a traffic stop for a broken tail light, and we are going to watch this case with a magnifying glass". She said he had a gun on him but told the officer about the weapon and also had a permit to carry a gun in the state. The woman says an officer shot her boyfriend.

The woman in the video said the man she identified as her boyfriend was reaching for his ID and wallet when the officer shot him.

"Our nation is in trouble", she said.

On Thursday, Reynolds accused the St. Anthony police of racism and poor treatment of her and her young daughter, who was also in the auto at the time of the shooting.

Police say the group made their way to a nearby commercial street where they broke the storefront window of one business as well as windows of an unattended police squad vehicle.

"He stood out because he was happy, friendly and related to people well", she said. I want justice, I want peace.