South Carolina police officers have been involved in more than 200 shooting incidents in the past five years, almost all of which were deemed justified and undeserving of criminal charges.

The difference between those cases and the shooting that led to a murder charge against North Charleston Police officer Michael Slager is that he faced no apparent danger when he gunned down an apparently unarmed, fleeing man Saturday, according to experts in police use of force.

Samuel Walker, a professor emeritus at the University of Nebraska who specializes in police accountability, called the video of Slager’s shooting of 50-year-old Walter Scott “absolutely outrageous.”

“This person is fleeing. He does not have a gun, he hasn’t stopped to turn,” said Walker, who testified earlier this year before the President’s Task Force on 21st Century Policing. “There is absolutely no justification for that shooting.”

Scott’s killing came at a time when police-involved shootings have stoked racial tensions and community unrest across the nation, from Ferguson, Mo., to New York City. The national dialogue, punctuated by chants of “black lives matter” and “I can’t breathe,” has focused on the often brittle intersection between law enforcement and race, and the extent to which deadly force can be used to keep the peace.

The nation’s highest court ruled in a 1985 Tennessee case that officers can use lethal force to stop a fleeing suspect if there is probable cause to believe that offender poses significant harm to the officers or others.

But simply trying to get away — as it appeared Scott was trying to do in a bystander video that surfaced Tuesday — doesn’t meet that standard, experts said.

According to the statement from the officer’s lawyer. Slager shot at Scott after the suspect took his Taser during a struggle, causing the officer to feel threatened.

But David J. Thomas, a professor and former police officer who serves as a senior research fellow with the Washington, D.C.-based Police Foundation, said he saw no evidence of a deadly threat in the video of the encounter.

“From what I just saw in video, the guy was just running away,” Thomas said. “It’s very tragic. This should have never happened.”

Seth Stoughton, a former police officer and law professor at University of South Carolina, said it was too early for him to pass final judgment on the case, but “the video looks pretty bad.” He said he was particularly troubled by Slager appearing to move the Taser closer to the body after the shooting. The officer also made no attempt to chase after the fleeing Scott before opening fire, shouted no commands to stop and made no attempt to quickly render aid to Scott after the shooting, as police are trained to do, he said.

“I have a hard time viewing this video and believing that this is anything that is going to be justified,” he said.

Though charges came quickly after the video surfaced, obtaining a conviction against Slager will be another challenge altogether. Murder charges can be difficult to prove against police officers, particularly those claiming to be acting in self-defense in the line of duty.

In January, former Eutawville Police Chief Richard Combs dodged a murder conviction in Orangeburg County after his trial in a 2011 shooting of an unarmed man ended in a hung jury. Prosecutors argued that Combs killed Bernard Bailey in a senseless act of violence, but Combs’ claims of self-defense sowed doubt in jurors’ minds.

Then again, there was no video of those fatal shots being fired.

“All cases where an officer is claiming self-defense are problematic,” said David Klinger, a professor at the University of Missouri-St. Louis and a former Los Angeles police officer. “However, if there is video evidence that indicates that self-defense claim is not warranted because the individual is not threatening a life, that is a very dicey proposition for the officer.”

Klinger said the end result of the case is that it could make life more difficult for other officers by damaging police relations and trust with the community.

Walker said North Charleston leaders took a step in the right direction by addressing the community, supporting the arrest of the officer and strongly condemning his alleged actions. “Both the mayor and the police chief appeared very concerned by this, and they appeared to have done the right thing given the evidence,” he said.