CHARLOTTE, N.C. — It’s one of Charlotte’s biggest mysteries. 

Eleven years later and we still don’t know what happened to Kyle Fleischmann. The 24-year-old vanished after a night out with friends in uptown.

We traveled to Hilton Head to sit down with his parents and also talked to detectives in Charlotte.

His parents seem convinced they know what happened. They fear he’s buried under an apartment complex that was under construction at the time.

But they are frustrated there is no way to prove it. All these years later, there’s no body, no great witnesses, no real evidence -- just a lot of questions and a heartbreak that never goes away.

Barbara Fleischmann said time has helped to dull the pain after Kyle disappeared from uptown in November 2007.

"It's true what they say about time," she said. "I like to think of the good things, think of the life, not the death. Mostly the good things."

Kyle's father, Dick, has a tougher time. 

"My brain tends to go towards, did we miss anything?" he said.

Dick said it's harder for him to focus on the good because he was so involved -- and is still so involved -- in the search for answers.

The outgoing, handsome Elon grad had been out with friends and ended the night at Buckhead Saloon. Cameras caught him walking on College Street towards 6th Street near Fuel Pizza. That was the last time anyone saw him.

"What do you think happened?" we asked.

"It’s a true missing persons case. We really don't know what happened," said Det. John Tuttle.

It was closing time, and Kyle had left his wallet and coat at the bar. He’d made several calls to his best friend, his sister, and dad -- probably looking for a ride home. It was after 2 a.m. He didn’t reach anyone, and he didn’t leave any voicemails.

RELATED: 10 years later: Detectives continue following leads on the Kyle Fleischmann case

"I just think he was a victim of robbery; it got bad, and they took his life," Dick said.

Dogs tracked Kyle’s scent to NoDa, near where construction was just getting started on new condos. Eleven years ago, it was a neighborhood in transition.

"There's condos now. We tend to believe he’s buried under there. At the time there was open dirt because they were digging for the pipes," said Dick.

Dick said searchers that day remembered a bad smell, and years later, people living there did as well.

"Three years later, a woman contacted the police. She goes, well, I called the police, there was a horrible stench here, and I said there’s something deceased here," said Dick.

Kyle’s parents have worked with a private investigator for years trying to get answers.

"I think we know but it's never gonna be prosecuted or anything like that. We know what our PIs have found out and the police to a lesser extent but nothing provable," Barbara said.

The Facebook page Kyle’s friends set up in the early days of the search is still active. People often weigh in. Strangers are still fascinated by this case all these years later.

"It resonates with people on so many different levels -- comes from a good family, college graduate, hard-working. He could be anybody; he’s the guy next door," said Det. Tuttle.

Dick still makes a point to track the page and respond when he can. They have moved on, they say, as much as they can.

"I hate to say it, it's hard to remember the sound of his voice, and sometimes it's hard it's not there but that’s the gift of time," Barbara said.

"There's never a day I don’t think about him," said Dick.

Barbara can't help but get wistful. 

"I wonder what he’d be doing. I see all of his friends getting married and having children, and I assume he would be doing that, too, and that would have been wonderful," she said.

If you have any information on this case, call Crime Stoppers at 704-334-1600.