ATLANTA >> Stanley Nelson writes for a small weekly newspaper in the Louisiana delta. For the past four years, he has been obsessed with one story: who threw gasoline into a rural shoe repair and dry goods shop in 1964 and started a fire that killed Frank Morris?

No one disputes that the death of Morris, a well-liked businessman who served both black and white customers, is connected to the Ku Klux Klan. The case is on a list of unsolved civil rights murders the FBI released in February 2007, the day Nelson first heard of the story.

But for a lengthy article that appeared yesterday in The Concordia Sentinel, Nelson, 55, put together what he believes is a key piece of the puzzle. He names the last living person he says was there that night.

In the article, both a son and a former brother-in-law of Arthur Leonard Spencer, 71, a truck driver from rural Rayville, La., say he admitted to being involved in the fire. Spencer’s ex-wife, Nelson reported, said she had heard the same story from another man who was also there.

Spencer, by his own admission, was a member of the Ku Klux Klan. But in interviews with Nelson, he denied knowing or having been one of two men suspected of burning the shop in Ferriday, La., a small town near the Mississippi border that is the hometown of the famous cousins Mickey Gilley, Jerry Lee Lewis and the Rev. Jimmy Lee Swaggart.

Spencer has not been charged, and the FBI has not said whether it is investigating him; however, he told Nelson after the article appeared Wednesday that the FBI had interviewed him within the last two months.

Spencer could not be reached for comment at his home or at Jimmy Sanders, a farm supply store where he works. His co-workers said he had gone to the hospital for blood tests.

Bettye Spencer, 67, was married to Spencer at the time of the fire. In an interview on Wednesday by phone from her home in Rayville, La., she said she had never heard anything about the alleged crime. The FBI visited her a few months ago and she told them that she had been a young mother when Spencer left her for another woman. That woman and her son are both sources in the article linking Spencer to the fire.

Bettye Spencer is still close to her former husband and said she talked to him early Wednesday. He was surprised people were trying to connect him to the fire.

“I’m telling you he had nothing to do with this,” she said. “We’re just old country people and I don’t understand where this is coming from. This is 46 years ago and now people are digging up bones?”

Unlike many of the 110 civil rights murders being investigated by both the FBI and journalists who operate under the umbrella group called the Civil Rights Cold Case Project, the story of Morris’ death stands out because it is one of a handful in which someone believed to be connected to the episode is still alive.

“The big concern about all of this is time,” Nelson said. “The time to solve these cases is maybe another year, or another two years maybe. People are dying.”

The FBI investigated the killing of Morris, who was 51, twice in the 1960s, and took up the case again in 2007. After the most recent investigation, The Sentinel and other organizations criticized the speed with which the FBI and the Justice Department have approached the civil rights cold cases.

Cynthia Deitle, chief of the FBI’s civil rights unit, told the newspaper that federal officials were actively working on the case and that she believed people were still alive who knew who killed Morris. She reiterated her agency’s dedication to what she called “one of the most horrific and troubling of all the FBI’s civil rights era cold cases.”

The link to Spencer is based in part on the newspaper’s interviews with his son, William Spencer, known as Boo. William Spencer told Nelson that he was trying to turn his life around after getting out of prison and finding religion.

William Spencer said he heard his father recount on more than one occasion the story of the fire. The elder Spencer was one of at least two white men who headed there in the early morning hours, intending to burn the shop as a message to the black owner, whom Klan members believed was too friendly with white female customers. The men did not expect the shop owner to be inside, the son told The Sentinel.

“My dad said they could hear a stirring in the place, then a man came out,” the younger Spencer said. Morris apparently had come out of the store to find men splashing gasoline on the floor and was forced back inside. Burned so badly that nurses could not recognize him, Morris lived for four more days. He gave interviews to the FBI but never identified his attackers.

“Son, it was bad,” the younger Spencer recalled his father saying. “I’ll never forget it.”

Arthur Spencer’s former brother-in-law, Bill Frasier, told the newspaper that he, too, had heard the story from Spencer.

The newspaper reported both William Spencer and Frasier had told their stories to the FBI. The agency would not comment on the case, but a spokesman pointed out that prosecuting an arson in federal court might pose challenges. The arson would have had to involve something that was a federal crime at the time, like interstate kidnapping or the use of a specific type of explosive, or it would have had to have happened on federal property.

It was Rosa Williams, Morris’s granddaughter, who moved Nelson to dedicate himself to this and the other cold cases. After he wrote his first article on the subject in 2007, in which he revealed that the owner of the shoe shop was on the FBI’s list of unsolved civil rights murders, Williams called.

She told him she had never known what had happened to her grandfather, and she thanked him. She also asked Nelson to help figure out who killed her grandfather. “I told her I’m going to try,” he said.

From that moment on, Nelson reported on little else. With the help of the Cold Case Justice Initiative at the Syracuse University College of Law, he went on to file more than 150 articles on the subject, culminating in this one, which he hopes will lead to an arrest.

But he is also motivated by the curiosity of a newsman.

“What kind of human being could set another man on fire?” Nelson said. “I was just curious about something that happened in our community that I never knew about. I just wanted to find out who did it.”