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MINNEAPOLIS (CBSMiami) – Hundreds of protesters demonstrated outside the governor's mansion in Minnesota following the deadly police shooting of a black man. The man's girlfriend live-streamed the aftermath of the incident on Facebook.

Diamond Reynolds told a crowd in Saint Paul that police killed her boyfriend Philando Castile for no reason.

"He didn't die do nothing, but what the police officer asked of us which was put your hands in the air and get your license and registration," Reynolds said.

Reynolds live streamed video of the moments following the shooting Wednesday night in a Saint Paul suburb. Reynolds said they were pulled over for a broken tail-light.

"He's licensed to carry. He was trying to get out his ID in his wallet out of his pocket and let the officer know that he was he had a firearm and he was reaching for his wallet and the officer just shot him in his arm," Reynolds explained.

The video shows the officer pointing his gun after the shooting.

Officer: "I told him not to reach for it - I told him to get his hand off it."

Reynolds: "You told him to get his ID sir, his driver's license. Oh my god please don't tell me he's dead."

"I wanted to put it on Facebook and go viral for the people to see it. I wanted the people to determine who was right and who was wrong," Reynolds said.

Protesters outside the governor's mansion said they're tired police killings like this keep happening again and again.

Gov. Mark Dayton said he asked the Justice Department to investigate.

"On behalf of all decent minded Minnesotans, we shocked and horrified by what occurred last night horrible tragedy," the governor said.

Castile was a cafeteria supervisor in the Saint Paul Public School System. Administrators said grief counselors will be available for students and staff.

The officer has been put on paid administrative leave.