What would have happened if the man with the cellphone had taken a different path to work?

After the video footage showing a white police officer in North Charleston, S.C., shooting an unarmed black man in the back propelled the case into the public eye this week, many people in the city and beyond questioned what would have happened without this recording. Some of them wondered if the officer’s narrative of a struggle would have ever been truly challenged.

Officials of the state agency investigating the shooting say that even before the video came out, they “were concerned” about inconsistencies they quickly found.

But this recording, which ultimately led to the officer’s arrest Tuesday as well as national outrage over what happened, only came to light because Feidin Santana happened to be there on Saturday morning while walking to his job at a barbershop.

Santana has said he considered erasing the footage because he feared for his own safety, though he ultimately decided to give it to the family of Walter Scott, the man who was killed. After the video came out, Michael Slager, the police officer, was charged with murder and fired from the police force. North Charleston’s police chief, Eddie Driggers, said he was “sickened” by the video. The mayor, R. Keith Summey, called it “a bad decision” and emphasized that it was an isolated episode.

Initial accounts from police and by that officer’s attorney in the days after Scott’s death described a struggle over a Taser and an officer fearing for his life. This narrative was directly contradicted by the recording that Santana took, which showed Slager firing eight shots at a fleeing Scott, and which was later provided to the state agency tasked with conducting the investigation into what happened. (Slager’s initial lawyer told The Post shortly before the footage went public that he was no longer representing Slager, who is now represented by a Charleston criminal defense attorney.)

The South Carolina Law Enforcement Division was alerted to the shooting shortly after it occurred on Saturday morning, dispatching agents and crime scene technicians to the grassy stretch where Scott was killed.

“There were inconsistencies including what appeared to be multiple gunshot wounds in Mr. Scott’s back,” Mark Keel, chief of the agency, said in a statement. “We believed early on that there was something not right about what happened in that encounter.”

These remarks were the first extended comments from the agency’s head since his agents arrested Slager and charged him with murder. They also seemed to be a response — intentionally or unintentionally — to assertions that without the video, the account offered by Slager would have gone unchallenged.

“It would have never come to light,” Scott’s father, Walter Scott Sr., told the “Today” show. “They would have swept it under the rug, like they did with many others.”

Police officers rarely face criminal charges after shooting people, a fact that has been cited by demonstrators protesting police actions across the country over the last year. The State, a newspaper in South Carolina, reported that officers there have shot at 209 people over the last five years; only a handful were accused of doing something illegal, and none of them were convicted.

Officers are allowed substantial leeway over how they use force, particularly when it involves killing to save themselves or others. A pair of Supreme Court rulings handed down in the 1980s govern when officers can use lethal or potentially excessive force.

In 1985, the court ruled in Tennessee v. Garner that police could shoot at a violent felon who was fleeing and posed a significant threat to others. Four years later, the justices ruled in Graham v. Connor that officers can use force if they have an “objectively reasonable” belief that a suspect is a safety threat or is trying to evade arrest, as Chief Justice William Rehnquist wrote in the court’s opinion. This “reasonable” standard has to allow for the reality that police often have to make rapid decisions “in circumstances that are tense, uncertain, and rapidly evolving,” as Rehnquist put it.

Legal observers this week said it is hard to know what will happen as the case progresses, warning that the videos still do not capture the entire confrontation. Still, they said that based on the video of the actual shooting, it did not appear it would be justified under the law.

“If there’s something outside that video we don’t know about, that may change this,” David A. Harris, a law professor at the University of Pittsburgh, said in an interview. “But from what we can see here, this appears to be a man moving away and any threat he might have posed in the recent past receding along with him.”

Dash-cam footage from the officer’s car, which was released Thursday by the state, does not capture the actual shooting. It shows the incident beginning with a routine traffic stop, and a little more than a minute after the stop, Scott is seen running away from the officer. The recording made by Santana, meanwhile, seems to begins shortly after and shows Scott and Slager appearing to struggle before Scott again runs away, at which point Slager opened fire. `

In this case, Scott was running away, and it is hard to imagine why Slager would have had to fire to prevent his escape, said David A. Klinger, a former police officer and criminology professor at the University of Missouri at St. Louis.

“The guy doesn’t run very fast,” Klinger said of Scott. “The officer’s clearly ambulatory, because after he stops shooting he runs up to the suspect. That’s a key component. It’s not merely that the individual is fleeing, it’s that the use of deadly force is necessary to prevent escape.”

Keel said he was informed on Saturday that his agents had concerns. Santana’s video, which was given to an attorney for Scott’s family and then provided to the state agency, “confirmed our initial suspicions,” Keel said.

State investigators have interviewed Slager and other officers on the scene, Keel said. He also suggested that the footage and interviews so far have highlighted other things of note to investigators, though he did not elaborate on what these might be.

“While what we have seen and learned may provide some answers, it raises more questions and issues to investigate,” Keel said.

Scarlett Wilson, the prosecutor for Charleston County, said her office was working with state agents to seek a grand jury indictment in the case.

“My role is to hold accountable those who harm others unlawfully, regardless of profession,” she said in a statement. “This office does not dictate nor comment upon police policy, training and procedure. I am, however, deeply concerned when those who are sworn to serve and protect violate the public’s trust.”