The brother of the man shot and killed by a North Charleston, S.C., police officer said the man who filmed the video of his brother’s killing did not at first release the video because the man wanted to see how investigators would handle the case.

“He wanted to see what reports were coming from the North Charleston Police Department because of the fact that they may have told the truth,” Anthony Scott said in an phone interview from home with TIME Wednesday. “And when they continued with the lies, he said, ‘I have to come forward.'”

On Tuesday, the officer who allegedly appears in the video, Michael Thomas Slager, was charged with murder in connection with Walter Scott’s killing. The video appears to show Walter Scott unarmed running away from the police officer before he was shot multiple times.

The man who filmed the video opened up in an interview that aired Wednesday night. “I knew right away, I had something on my hands,” Feidin Santana told NBC Nightly News.

MORE: Man Who Filmed South Carolina Police Shooting Speaks Out

“I was sickened by what I saw. And I have not watched it since,” North Charleston police chief Eddie Driggers said at a press conference Wednesday.

Anthony Scott, whose brother was pulled over in a traffic stop Saturday morning, said he first saw the video when approached by a man at a vigil for his brother earlier this week.

“I was angry. Shocked,” Scott said. “I said, ‘We have to have that.’ So that we could prove it was innocent.”

“I think that if that man never showed the video we would not be at the point that we’re at right now,” Scott said. “The video tells the truth. It would not be so hard for us to prove that this man was running away when you get shot in your back. I mean how can you defend that?”

In the interview, Scott recalled arriving to the scene of his brother traffic stop after he had been told his brother had been shot by a Taser gun to learn that his brother was dead.

“When I got there somebody told me that he was gone. And I was like what in the world? What happened? What happened? How did you get killed in a random stop? It just didn’t make any sense to me.”

Scott hoped his younger brother’s death and the video of his death will change how police officers operate throughout the United States: “My hope is that will change the way that officers conduct themselves across the country, not just here. Body cams would be an excellent idea, which would hold them accountable.”

Read next: Errol Morris: Documentary of a Murder

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Write to Justin Worland at justin.worland@time.com.