For decades, former Louisiana police officer Herbert Joiner used a brown leather briefcase to store the records, clippings and clues he had collected about a case that had haunted him since 1982 — the brutal gang rape and murder and 16-year-old Roxanne Sharp.

"Herbie," as he was known to friends and family, died in October, just a few months before the case that shook him and the city of Covington to its core was finally cracked.

But before he was felled at age 68 by a heart attack, Joiner had shared what was in the briefcase with the lead Louisiana State Police investigator on the case, Stefan Montgomery, Joiner's son and the LSP confirmed.

“I know him and Stefan had a sit down for a couple hours,” Justin Joiner, 39, told NBC News. “It was one of the few times I saw him excited about this case.”

On Friday, the Louisiana State Police announced that four men who had long been on Joiner's radar were arrested in connection with the Sharp murder by their cold case detectives based in Covington.

To broaden their net, the state police had partnered with local radio host Charles Dowdy of the Northshore Media Group to produce a podcast titled “Who Killed Roxanne?” in 2025.

That, police said, generated new information, leads and witnesses that had previously been unknown to investigators.

Also, DNA technology that hadn’t existed when Sharp was killed figured in the arrests of Billy Williams Jr., 62, Darrell Dean Spell, 64, Perry Wayne Taylor, 64, and Carlos Cooper, 64, police said.

“This case is a powerful example of what persistence, collaboration, and advancements in investigative technology can accomplish,” local District Attorney Collin Sims said after the arrests were announced.

Justin Joiner said he is convinced his father also played a role in bringing these men to justice.

“We all knew my dad had worked on the case,” he said. “We all knew he was frustrated. The years was going by and nobody was being held accountable. And the thing is the guys who were arrested, my father suspected it was them. They were part of this clique, they were always with each other.”

LSP spokesperson Trooper Marc Gremillion confirmed they had been in touch with Joiner prior to making the arrests.

“Regarding the briefcase, investigators have spent years gathering materials related to the case, including statements, photographs, and historical records from individuals connected to the investigation, such as Officer Joiner,” Gremillion said via email. “Due to the ongoing prosecution, we are limited in what we can confirm or discuss concerning specific evidence or items collected.”

In his obituary, Joiner was affectionately dubbed “a man of a million words.”

But Joiner almost never talked about what he saw on Feb. 12, 1982, when, as a Covington police officer, he arrived in a wooded section of the city and found Sharp strangled, his son said.

“He would rarely talk about it because he was one of the first officers to arrive at the scene,” Justin Joiner said. “And what he saw was traumatic. What happened to her was brutal. ... And the thing is, he knew the girl. We’re kin to the Sharps.”

Joiner, like a lot of people in this small city of some 11,000 residents, located across Lake Pontchartrain from New Orleans, was stunned by the sheer brutality of the murder, his son said.

“I was telling somebody just the other day that this killing has been like a big black cloud on the community,” Justin Joiner said. “Nobody would talk about it, especially not outside. It was all hush-hush, don’t talk about it outside the house.”

Dowdy, the radio host, said in an interview that he had reached out to the state police in search of a case to highlight and was astounded by how much the subsequent Roxanne Sharp podcast resonated with the Covington community.

“I made this remark early on about whether there was anybody around who still cared about what happened to Roxanne,” Dowdy said. “It turns out there were a lot of people in this community who were deeply invested in Roxanne’s story. They waited a long time for this case to be solved, for this to be over.”

In particular, Dowdy said, Sharp’s niece, Michele Lappin, “did not let this go.”

“It’s always meant something to us,” Lappin told NBC News on Monday. “But when the podcast came out, I realized it meant something to a lot of people.”

Roxanne, who was a young mom at the time of her death, had been missing for three days when her body was found, police said.

Not long afterward, a convicted killer named Henry Lucas claimed responsibility for Sharp’s murder but later recanted. Lucas, who died behind bars in 2001, was nicknamed the “Confession Killer” because he falsely claimed to have killed hundreds of people.

Then in 2023, for reasons still unclear, state police detectives began re-interviewing witnesses and potential suspects, going over the case file, and began gathering additional evidence and resubmitting original evidence for DNA analysis.

Joiner had kept tabs on the unsolved case long after he retired from the force and became a school bus driver, his son said. And any new clue went straight into the brown leather briefcase.

“We were not allowed to touch the case,” said Justin Joiner. "Not even as adults."

But Joiner did share the contents of his briefcase with the detective prominently featured in the podcast, Stefan Montgomery.

“Stefan Montgomery lived across the street from us and my father would talk to him all the time about the case, get updates,” Justin Joiner said. “He would come home and we could tell he was just beaten down and frustrated that the case wasn’t going anywhere.”

NBC News reached out to Montgomery for comment via the LSP. The agency declined to make him available but confirmed investigators had been in touch with Joiner.

Several months before he died, Joiner came home from a visit with Montgomery and he was very excited, he said.

“He knew they were getting closer and closer to connecting the dots," Justin Joiner said.