The case that's gnawed at Oconee County Sheriff's Captain Greg Reed is the senseless killing of 19-year-old Brooke Holsonback, a tragedy still tearing at the broken hearts of Brooke's parents, Warren and Debbie.

Brooke was the firstborn of the Holsonbacks' three children. Brooke had a special glow that enchanted everyone, even when she was just a little girl growing up in the small country town of Prosperity, South Carolina.

In high school, Brooke was a cheerleader and was the smartest girl in her class. She was accepted into nearby Clemson University when she was still just in the 11th grade.

"They sent her a letter and they told her to come up and that she could major in whatever she wanted," said Warren Holsonback, Brooke's father.

So after graduating from high school, Clemson is where she went to major in biochemistry.

"She was hoping that after she got through she can maybe do some cancer research, and who knows, maybe find a cure for cancer," said Warren.

But Brooke would never get a chance to achieve her noble ambitions.

Clemson University is a school known for its athletics and small-town appeal. But less than two miles from this picturesque campus, the freshman student lost her life. She was found dead on February 20, 1997.

The story of what investigators think may have occurred is told in a police recreation video made several years after her murder.

Around 9:30 one night, Brooke visits the dorm room of classmate Bryant Gallup, where he was hanging out with another student named Jeff Dubnansky.

"The guys wanted to go mud-bogging and both had been drinking a bit, so she was going to drive for them," said Capt. Reed. "They ended up at the mud bog and they got stuck."

Then Gallup and Dubnansky reportedly begin arguing and tussling. They said Brooke was nowhere in sight.

"According to them, she had just walked off," said Reed.

And when Brooke didn't return to the dorm, her roommate reported her missing to university police around noon the next day.

At almost exactly the same time, a worker sees Brooke's body floating in Lake Hartwell, near the muddy field where she had reportedly gone four-wheeling with Gallup and Dubnansky the night before.

At first it appeared Brooke had drowned. But Detective Reed would soon learn this was no accident: She died as a result of strangulation. At 19, she had been a student for less than six months.

Investigators say they think they know who did it, but they need more evidence before they can bring charges.

The coroner's investigation concludes that Brooke had been strangled after possibly being sexually assaulted.

"There had been some kind of sexual altercation because she did have some minute lesions and tears around the vaginal area," said Reed.

Minor abrasions were also found on other parts of her body, and Reed, then a detective-sergeant leading the investigation, immediately questioned the last people known to see Brooke alive: fellow students Bryant Gallup and Jeff Dubnansky.

"After their little wrestling match was over, according to them, she was gone. She had just walked off," said Reed.

They told Reed that when they couldn't find Brooke, it was decided Gallup would stay with the bogged car while Dubnansky went to get help.

"Brooke can't give her side of the story, so we're having to go on what they have to tell us, and it don't make a lot of sense to me," said Reed.

Captain Reed says he doesn't believe she would just walk away into the night in a dark, isolated area.

"Think about it: Why would you walk away, knowing that you have a long walk? Why would you walk away from the only security you thought you had? You wouldn't. You wouldn't do it. No young lady would do it," said Reed.

According to a police report, investigators observed bite marks on Dubnansky, who claimed he got them during his tussle with Gallup.

And Reed recalls something Dubnansky said happened when he crossed a bridge while walking to get help.

"He said that 'When I got to the bridge it sounded like someone had said something to me. So I looked up in the air and I looked all the way around and I just kept walking.' Well, he was only 50 yards from where Brooke's body was," said Reed.

Reed says Gallup also told him something that struck him as odd while he was watching investigators retrieve Brooke's body from the lake.

"While we were down there, he was sitting right up here on the road crying, and I asked him why he was crying," said Reed. "He said he just had a feeling that something bad had happened to Brooke."

But there was no evidence to connect Dubnansky and Gallup to Brooke's murder. Her body being dumped in the lake had washed off any DNA evidence, and nothing could be found at the field where Dubnansky and Gallup said they and Brooke had gone 4-wheeling.

"That night and then early the next morning after we did find Brooke's body, we had torrential downpours for a couple of days, and it was really, really bad, and it washed away whatever may or may not have been there," said Reed.

Gallup and Dubnansky were both administered polygraph tests. Reed said the polygraphers said that there were signs of deception on both of those.

Gallup and Dubnansky were never named as suspects, nor were they ever charged with anything in connection to the crime. They hired attorneys and refused to answer any more questions, leaving investigators with only their own theories about Brooke's murder.

"We really feel like she was placed in the water well before the vehicle becomes stuck. I feel like, 'let's get the vehicle stuck.' That's part of the alibi, she walked off. Can we prove that? No we can't," said Reed.

Reed also thinks Brooke may have been murdered after rebuffing sexual advances.

"I think that strangulation was them trying to get what they wanted," said Reed.

That theory was included in the police reenactment video of Brooke's murder.

Veteran victim rights advocate and South Carolina Crime Victims’ Council Executive Director Laura Hudson wanted to see Bryant Gallup and Jeff Dubnansky arrested and taken to trial, but prosecutors didn't think they had enough evidence.

"I looked at all the evidence there, listened to the experts that'd been employed by various law enforcement," said Hudson. "I felt there was enough of a case to carry it forward. But prosecution didn't agree."

And after Brooke's murder, both Gallup and Dubnansky moved out of state.

Reed actually took a team to Virginia Beach, Virginia, to keep Gallup under 24-hour surveillance for a month.

Reed personally delivered a copy of the police reenactment video to Gallup.

"And I told him that I wanted him to know that I was never going away, that he needed to remember me, and that he needed to remember Brooke," said Reed. "And then I handed him the tape and I turned around and walked off."

Both Gallup and Dubnansky did not respond to numerous attempts by Crime Watch Daily to get their side of the story.

Captain Greg Reed urges whoever killed Brooke Holsonback to come forward. And Brooke's deeply religious family still believes whoever killed her will eventually face justice, one way or another.

Bryant Gallup and Jeff Dubnansky have not been called suspects in this case, nor have they been charged with anything related to it.

If you have any information regarding the unsolved homicide of Stacey Brooke Holsonback, you are asked to call Crimestoppers 1-888-CRIME-SC, or text in your tip to 274637. If your tip leads to an arrest, you could be eligible for a cash reward of up to $2,000.