South Carolina doesn't allow face-to-face interviews with inmates. However, over the course of five recent phone calls, Brown allowed News10NBC to record the conversations for broadcast. And he provided what he claims is his first-hand account.

Brown says he first saw Brittanee Drexel at an abandoned house in McClellanville, South Carolina in April 2009 -- two days after Drexel had disappeared.

Taquan Brown: "On this Monday, April 27, I saw the girl..."

News10NBC's Brett Davidsen: "In the stash house?"

Brown: "Yeah. There was about 8-12 guys in there."

Brown says Drexel had a black eye and was being sexually assaulted.

When asked if he recognized her right away, Brown said, "No. I didn't even know who she was. I didn't know who she was until actually a few weeks later when everything started coming on the news."

Over the phone, Brown described the abandoned stash house to News10NBC, and it was consistent with the house we saw when we went to McClellanville to investigate in 2016.

He says he returned to the house a few days after the first visit.

"We was in the front yard and the girl ran out the back door and four other guys ran behind her and they hit her and brought her back inside," Brown recounted.

Brown says he then heard gunshots and assumed Drexel had been killed.

"As I get in my car, I see two gentlemen come out the house with a rug and they put it in back of his truck. And I left," he said.

But Brown says, five days later, he went to visit his cousin Herman at his house in rural Jacksonboro, South Carolina -- to show him a car he had just bought.

The home is on a sparsely populated dirt road about 80 miles away from McClellanville.

Brown: "When I stopped by to show him the car, she was there."

Davidsen: "Alive?"

Brown: "Yes, she was alive. She was at his house."

Taquan Brown's name first surfaced in 2016 during a detention hearing in federal court involving a man named Timothy De'Shaun Taylor.

An FBI agent testified that they had received information from Brown who said Taylor had direct involvement in Drexel's kidnapping.

News10NBC spoke with Taylor in 2016. He denied ever meeting Brittanee Drexel.

"The only thing I've known is what I've seen on TV and bulletins and what the FBI has been telling me," said Taylor in that 2016 interview.

He also claimed he had never seen Taquan Brown before. But court records show Taylor failed a polygraph about the Drexel case.

Brown claims that Taylor was at the stash house.

As for the murder, he says he and a friend witnessed it while walking to his cousin Herman's house in late May 2009. Brown says he saw a group of men with Drexel -- including a man he only identified as "Nate."

"There's a wooded area on the property line. So we were walking through the path and the shooting took place," Brown said. "Nate shot her with a double-barrel shotgun two times."

Brown says they turned around and left, so as not to be implicated.

Much of Brown's account is consistent with, and even more detailed than, what the FBI has stated publicly. However, there are major parts of what Brown told News10NBC that we've been unable to corroborate.

For instance, the man he was walking with when he says he witnessed the shooting -- we were unable to track him down. His cousin Herman has since died of a heart attack. A third person Brown identified as an eyewitness was murdered in 2016.

Still, he says there are many who witnessed Drexel's captivity.

"There's several people who actually, at some point in time throughout that month, however long it was, that went back and forth to Herman's house who actually seen her back there," he said.

De'Shaun Taylor has not been charged in connection with Drexel's disappearance. His new attorney had no comment about Brown's statements.

So is Taquan Brown to be believed?

Brown claims he took, and passed, a polygraph administered by the Charleston County Sheriff's Office.

The FBI went out on a limb two years ago, stating it had witnesses that would back up Brown's account of what happened to Brittanee and openly called Taylor a target of the investigation.

But still, no arrests.

We reached out to the FBI to find out if they still believe Brown is a credible witness.

A spokesperson would not say. However, he did confirm that agents met with Brown in prison just last month.

In an emailed statement, the FBI says, "The investigative team for Brittanee's kidnapping is constantly assessing and evaluating all information provided to it. We continue to receive leads from South Carolina and beyond and follow up on everyone. Brittanee's mother has access to the investigative team and recently met with them. This matter continues to remain a priority and has every resource available. "

Brown confirms he spoke with several law enforcement agents at the prison last month.

"They told me things was slow and that they're in the process and they told me to be patient," he said.

Brown says he was not promised any deals in exchange for his cooperation. He says he came forward after he and his mother received death threats. He says he agreed to speak with authorities in return for his mother's protection as well as his own.

But Brown says he's also frustrated that nothing came from his cooperation, and last week, he filed a lawsuit against several investigators, claiming they put him in danger by releasing his name to the public.