Video could be key as ex-cop goes on trial in Walter Scott killing

Slager killed Scott after pulling him over for a broken brake light on April 4, 2015. But it wasn't until days later that the public learned about the case when The New York Times published footage of the shooting.

The cell phone video, recorded by a bystander, shows Scott running away, his back turned. The officer raises his gun and fires eight times. Scott falls to the ground. Motionless and face down in the grass, the officer handcuffs him as someone yells, "Put your hands behind your back!"

The graphic video sparked outrage and reignited a national conversation about race and policing. Scott was black; Slager is white.

For weeks after the shooting, mourners stopped by the empty lot where it happened to pay their respects.

Activists in the community said it wasn't the first time they'd spoken out about police brutality. But the cell phone video, they said, was a game changer that forced authorities to acknowledge their concerns.

Slager was arrested after the shooting. A grand jury indicted him on a murder charge in June 2015. The former officer has pleaded not guilty. If he's convicted, he could face 30 years to life in prison.

He was released from jail on bond in January and placed on house arrest.

City officials swiftly announced that Slager had been fired.

"I have watched the video, and I was sickened by what I saw," North Charleston police Chief Eddie Driggers said at the time.

Slager's defense has said he's eager for the trial to get started so he can tell his side of the story -- but the lawyers don't want him to do it in the county where the shooting happened.

The former officer's defense team argues that there's a "toxic stew of half-truths, misperceptions and false narratives" surrounding the case in North Charleston, where city officials settled a civil suit with Scott's family for $6.5 million and where the video has been widely seen.

But so far, the trial is staying put. It's set to take place in a county courthouse in the neighboring city of Charleston.

The video is far from the only evidence in the case, but there's no doubt it will play a major role in the trial.

The defense argues it doesn't clearly depict the lead-up to the shooting -- key moments that they say show Slager was acting in self-defense after Scott tried to grab his Taser. Slager used his Taser on Scott, then the two got into a scuffle, they contend. "The video of the fight is blurry and indistinct, while the video of the shooting itself is clear. As a result, the video is rarely if ever, shown in its entirety," the defense said in a recent motion obtained by CNN affiliate WCSC-TV in Charleston.

Solicitor Scarlett Wilson has argued it's not just what the video shows of the shooting that's troubling. She says it also shows that Slager -- a veteran emergency medical technician officer -- "put handcuffs on a dying or dead Walter Scott" rather than trying to render aid.

Attorneys for Scott's family have argued the video shows Slager trying to plant evidence at the scene, moving a Taser closer to Scott's body.

Accused Charleston church shooter Dylann Roof is set to go on trial November 7 at the federal courthouse across the street.

Police told reporters this month they're stepping up security in preparation for the high-profile cases.

"This is going to be a very delicate and important time for the city," Charleston police Chief Greg Mullen said. "There's going be a lot of emotion and a lot of activity around the courthouses."