NASHVILLE, Tenn. -- A dedicated rape detective said he had a 30-year gut feeling about the Marcia Trimble case.

Sgt. Ralph Langston was the first to put Jerome Barrett in jail in Nashville.

He said he was putting the pieces together back in 1975, but no one would listen. Nobody had computers, or a database, and it was rare for police to share files or even compare notes.

The thinking then was that 9-year-old Trimble had to have been slain by someone she knew. Trimble was last seen alive in the Green Hills area while delivering Girl Scout cookies. Her body was discovered about a month later in a garage barely 100 yards from her home.

After 32 years, Langston explained how he put his theory together.

Langston gave up his badge almost 14 years ago. But he said he’s never given up the hunch, a highly analytical hunch, that Barrett killed Trimble.

He said it began with Barrett's clothing.

“Heavy wool tweed, what I would call, a heavy wool tweed, dark overcoat, dark pants, thick boots at that time, a bandana, and I can’t remember if it was red or white, but it was one of those cowboy, all you can describe it was as a cowboy bandana and cheap work gloves. I said, ‘Well, you mean, leather, whatever,’ and they said, ‘No. It was a cloth,'" he said.

Three women had been attacked in a matter of weeks in 1975. Every one of them described the man's clothing perfectly.

Langston said he was sitting in a courtroom waiting on another case when it happened.

“Vanderbilt officers brought in a suspect for trespassing and there he stood. It was Jerome Barrett,” he said. “It was like somebody smacking me in the face because I had taken so many of that description. There’s that description standing in front of me.”

Once Barrett put on a jail uniform, Langston took all his clothes.

Immediately, Langston said, the rape victims recognized the coat and gloves and were able to identify their attacker in a lineup.

“(There) was no hesitation. He was picked out I know for the first one, now we’ve got him here, let’s start doing some background,” he said.

They went to 1712 Jefferson St., which is now a barber’s shop. Back then, it was a rooming house in which Barrett rented room No. 17.

“That's when we found the jewelry. … I don't think we ever identified but maybe a third of that stuff, so we knew there were other victims out there, just didn't know who at the time,” he said.

Barrett would later be linked to two rapes and two attempts, police said. He was found guilty of raping a Belmont student and sent to prison.

But Langston said he was convinced Barrett had done much more, and all on foot.

“He was the truest predator you'll ever see,” he said.

Langston said Barrett would walk the streets and knew every alley and shortcut.

“He's watching for these opportunities and he got them,” he said.

After a long interrogation, he said, Barrett cried while he confessed, but only to crimes police knew about.

Then Barrett had a strange reaction, Langston said.

“I didn't bring up the case, I brought up the street. … 'What about the street, Estes Street, right up there?' And I remember him hitting (the table), ‘You’re not going to pin that on me.’ I said, ‘What are you talking about? I’m just talking about the area where you worked.’ ‘That little girl, you're not going to pin that on me.’ He wouldn’t open his mouth again,” he said.

Langston talked a lot through the years by asking different colleagues to consider Barrett as a suspect in the unsolved slaying of Vanderbilt student Sarah Des Prez and in the Trimble case.

“Have you all still not thought this might be an unknown, random suspect? And I was made to feel like an idiot anytime I brought it up. … I said, ‘Why do you know it's a known suspect when nobody knows nothing?’ So would put it on the back burner, because every time I would bring it up, I would feel like an idiot. So, I let that go and let it go. … I never forgot it. I said, when we get back to Nashville…I want to see justice is done for those families because they deserve that,” he said.

Two of the longest-running slaying mysteries in Nashville could be over. Barrett is charged in the slaying of Des Prez and Channel 4 has confirmed that Barrett will be charged in the raping and slaying of Trimble.

“I'm not seeking glory in none of this. There are two families out there that need closure and justice, that's why I took that job, I loved it,” he said.

He said he loved putting people like Barrett away.

“‘I've been fighting this Belmont rape conviction for years,’” he said, mimicking Barrett. “Well, keep fighting it, because I put you there.”

Langston said he's positive Barrett also raped a schoolteacher in 1975. She never prosecuted. After seeing Barrett’s fingerprint on a police report, reporter Demetria Kalodimos asked Langston why the there were never any fingerprints in the Trimble case to analyze.

He said Barrett always wore cheap, cloth gloves.