Bobby Daniels Jr., foreground, and his stepmother, Cynthia Daniels, discuss the details of that fateful day when his father was fatally shot in Douglasville, Ga. (Matt McClain/The Washington Post)

Bobby Daniels was the neighborhood Mr. Fix-It, the guy you called in search of a hard-to-find tool, or when you weren’t quite sure how to patch the doorknob-sized hole in your drywall. Some summer days, neighbors say, you’d glance out the window to see Daniels on his riding mower, cutting that grass you had let grow a bit too long.

But most often Daniels could be found under the awning of his rancher, methodically working on “Mr. Brown,” his cream and brown, early-’90s-model GMC truck.

And that is where he was, four days before Christmas, when he got the call: His son Bias had gotten violent at a mobile-home park nearby. The teen was probably high on drugs, had a gun and had taken a security guard hostage.

Daniels, a CNN security guard retired from the military, dropped his tools, jumped in his car and beat police to the scene.

The city of Lithia Springs is about 20 minutes west of Atlanta. (Matt McClain/The Washington Post)

Minutes later, the popcorn crackle of gunfire pierced the air, and Daniels, 48, lay on the ground, mortally wounded by a local sheriff’s deputy.

As was often the case in the 990 fatal police shootings in 2015, what exactly happened in those crucial moments before the trigger pull is in dispute.

There is agreement that when police responded to the scene and began to detain Bias Daniels, his gun was no longer in his hand and had been set down on the hood of the car. Then, he broke free and made a move for the weapon, and the stories diverge on what happened next.

Family members say Bobby leapt from his car and tried to knock the firearm away from his son. Police say the father and son both grabbed the gun, struggling over it, with the muzzle ending up pointed at a sheriff’s deputy who opened fire.

Bobby Daniels’s dying act, his family insists, was an attempt by an innocent man to keep his 19-year-old son from doing something that could have gotten him, or the officers, killed. They want the officer charged with murder or manslaughter and the video of the shooting released.

Their calls for accountability come amid a national push toward policing reform; however, historical and legal precedents make it almost certain that the officer who killed Bobby Daniels will not face criminal charges.

Because the deputy saw a gun.

Daniels’s grave is seen at Georgia National Cemetery in Canton, Ga. (Matt McClain/The Washington Post)

Family members say Daniels was trying to defuse a situation involving his son, Bias Daniels. (Matt McClain/The Washington Post)

Officers are rarely charged with crimes for on-duty shootings. While no one keeps accurate historical data on police shootings, a Washington Post analysis of what has probably been more than 10,000 on-duty police shootings since 2005 identified just about 70 shootings for which an officer was charged — and only two of those shootings were cases in which a gun was recovered at the scene. Last year, the person who was killed had a gun in 569 fatal police shootings.

In 1989, the Supreme Court established the “objective reasonableness” standard for assessing a civilian claim that an officer used excessive force in making an arrest. In its decision in Graham v. Connor, the court established a precedent that, for example, an officer who shoots and kills someone did so because he or she perceived a lethal threat that another “objectively reasonable” officer would also perceive, that shooting is justified. The court also held that the judgment “must embody an allowance for the fact that police officers are often forced to make split-second decisions about the amount of force necessary in a particular situation.”

Policing experts, chiefs and training officers note that in a nation of more than 300 million guns, there is no threat more lethal to law enforcement than the presence of a firearm in the hand of a potential suspect.

“Our use-of-force training is so wrapped in one issue: the fear of the gun,” said Tom Manger, chief of police in Maryland’s Montgomery County, during a major gathering last month of policing experts in Washington, D.C. “That permeates everything we do in terms of training and use of force.”

The Washington Post has investigated details surrounding those who died from police shootings, and here are six important takeaways.

Attorneys for Daniels’s family say he was still begging his son to put down the weapon when officers arrived. Eventually it was set on the hood of a car. But the boy made another desperate attempt to grab the weapon. His father jumped up as well. Then gunshots.

Rosa Brown, who has lived in the mobile-home park for six years, says she was sitting on her bed when she heard the screaming coming from outside her window. “Put down the gun, put down the gun,” was being yelled at a young man standing directly in front of her home. Then she heard the loud “boom.”

“I ran straight to the space between my washer and dryer,” Brown said, waving her arms in reenactment. “This is a trailer — those bullets could have come right through the wall and killed me.”

Bias took off running. The deputies chased him and caught up with him just around the block.

Back outside Brown’s trailer, the boy’s father lay sprawled on the cold gravel, blood pouring from the hole in his chest.

Rosa Brown lives in Arbor Village mobile-home park and could hear screams from her window. (Matt McClain/The Washington Post)

That night, with reporters beginning to gather, Sheriff Phil Miller stepped to the microphones and cameras.

The leader of a department of 237 sworn deputies, Miller made national headlines in late 2013 when he declared he was banning A&E from filming in his county after the cable network suspended embattled “Duck Dynasty” star Phil Robertson. Last September, Miller hit the news again after purchasing “In God We Trust” bumper stickers for department vehicles.

He has handled “four or five” fatal police shootings since first being elected to office in 2001, in addition to several deaths in custody at a local prison supervised by his deputies.

His deputies that evening had answered the 178th service call in six months at the Arbor Village mobile-home park. A security guard told them he had been held hostage for 45 minutes by a young man with braided hair and a gun. As they spoke, Garrett Daniels, Bobby’s nephew and Bias’s cousin, found the deputies and directed them to the ongoing incident.

When they arrived, the deputies found Bias, Bobby and the gun.

“I think that he could have been trying to help the situation instead of hurting it, but when he pointed the gun at the officers, he was shot,” Miller told reporters that night, later calling the slain man a “suspect.”

The account infuriated Daniels’s wife, Cynthia, and his four other children. Daniels had extensive training with firearms, which he also collected. Among his closest friends, his family insists, were police officers. There is no way, say the Danielses, who describe themselves as “yes ma’am and no ma’am type people,” that Bobby grabbed the gun and pointed it at an officer.

Cynthia, left, and her daughter, Shequila Hughley, recount mixed emotions. (Matt McClain/The Washington Post)

“How do you defeat police-brutality cases? It’s to get the general public not to care,” said Chris Stewart, an Atlanta civil rights lawyer working with the Daniels family. “The quickest way to do that is to have the person depicted as a thug, high on drugs or endangering a police officer.”

“The problem is that their usual narrative doesn’t fit Bobby Daniels,” he said.

Why, the family wants to know, was a man desperately trying to save his son described by the local sheriff to the media as a suspect?

“That’s my fault,” Miller said in an interview with The Post. “Everybody wants us to get this information out to them as soon as possible. But the quicker you give out information, the less the likelihood of it being accurate.”

More than two months after the shooting, another crucial question rests at the heart of the conflicting accounts: Did the Douglas County sheriff’s deputies know who Bobby Daniels was when they opened fire?

Miller says Deputy James Barber, a military veteran who fired the fatal shot, had no way of knowing whether Daniels was there to help the officers or potentially hurt them.

Garrett Daniels said he told both deputies before he sent them to the scene that the father was there, trying to defuse the situation.

Finding their suspect’s gun on the car, Deputy Josh Skinner began to handcuff Bias Daniels, who then struggled, Miller said. Skinner tried to use a stun gun; then Bias broke free and made a dash for the weapon.

That is when, according to Miller’s account, Bobby Daniels leapt from his seat in his car and began struggling with his son over the gun. At some point in the struggle, Miller said, the weapon ended up pointed at Barber, who opened fire.

“He is ordered to stay in the car and he refuses to,” Miller said. “There were four deputies there, and not one of them knew who Bobby Daniels was.”

Family photographs are seen in the home of Bobby Daniels and his wife, Cynthia, in Lithia Springs, Ga. (Matt McClain/The Washington Post)

Local reaction to the shooting, just days before Christmas in a city where there are more church steeples than storefronts, was muted. There was coverage on some of the television channels and the big newspaper in Atlanta, but soon the storyseemed to die down.

There were no protests in Douglas County, a racially diverse stretch of Georgia that rests along Interstate 20, a dividing line between the black communities surrounding Atlanta and the white rural communities to the north. Local black residents shy away from the sweeping indictments made by minorities in many of the cities where there have been controversial police shootings.

“I’m really proud of the progress we’ve made,” said Kimberly Alexander, who after founding the local NAACP chapter was elected to represent Douglas County in the statehouse. She praised Miller’s willingness to be forthcoming about the details of the shooting and said she hopes the incident will buoy discussions about getting body cameras for local deputies.

“Of course, I’m going to be concerned about a situation in which a man arrives on the scene to comfort his son and ends up being shot. It’s disheartening and disturbing,” Alexander said. “But we also have to allow for the process to play out.”

“It just doesn’t make sense,” said Bobby Daniels Jr., the slain man’s oldest son, who traveled back to Georgia from his home in Indianapolis to help his family sort out what had happened. “The story, from the night of it, has been ever-changing.”

“It just doesn’t make sense,” Bobby Daniels Jr. says of his father’s fatal shooting. (Matt McClain/The Washington Post)

Investigators with the Georgia Bureau of Investigation, which is handling the probe, say there is some video of the shooting, captured by a surveillance camera installed at the mobile-home park.

Daniels’s children are eager to see the footage, which they hope will prove once and for all that their father died in an act of selfless heroism. On Friday, Daniels’s family held a news conference again urging authorities to release the video, but state investigators have yet to say when, if ever, the video will be released.

Miller, the sheriff, declined to comment on whether he has seen the video evidence. But he predicts his deputy will be cleared of wrongdoing by local prosecutors.

“It’s a very tragic story — one where all of the wrong things came together at the wrong time — and, as a result, a man lost his life,” Miller said. “It breaks our heart.”

Daniels moved his family to a neighborhood just outside Douglasville about four years ago, in pursuit of a quieter life nestled just far enough from the city to have a little green space but not too deep into the Georgia plains.

“I miss my boo,” Cynthia Daniels said, as the family gathered at their home on what would have been Daniel’s 49th birthday. The folded American flag handed to her at the funeral rests in a living-room cabinet. “I just want him to come back through that door.”

They got married in 1996, pulling up to the courthouse to sign the marriage license in Daniels’s favorite project, Mr. Brown. Now the old truck sits in the driveway where Daniels left it two months ago, its paint chipped and fading.