The Darkest Night: The 13-year-long investigation into murder of a missing teen

It was a case that kept a Rochester family on edge for 13 years and kept the nation in suspense as investigators searched long and hard for the high school junior who vanished in Myrtle Beach, South Carolina.

Dawn Drexel will never forget the moment she got the phone call informing her that her teenage daughter was missing.

In April 2009, Brittanee Drexel told her mom she would be spending a few days at a friend's house in Rochester, New York. Unbeknownst to Drexel, her 17-year-old daughter was, in fact, over 800 miles away on a spring break trip in Myrtle Beach, South Carolina without her permission.

In an exclusive interview, Drexel told "20/20" that she didn't want her daughter going on a trip unsupervised. “I said, ‘There's no parental supervision,’ and I said, ‘Something is going to happen to you,'" Drexel said.

Brittanee was last seen leaving a Myrtle Beach hotel lobby and was never seen again.

“It's just a parent's worst nightmare,” Drexel said.

Drexel searched tirelessly for Brittanee, desperate to know what had happened to her daughter. It would take 13 years for her family to finally begin to get some answers.

This past May, Raymond Moody, who had been a person of interest for over 10 years allegedly confessed to killing the teen and led law enforcement to her remains, according to Fifteenth Judicial Circuit Solicitor Jimmy Richardson in an interview with ABC's Charleston affiliate WCIV.

"20/20" reveals new details about the investigation into Brittanee Drexel’s murder in an episode scheduled to air Oct. 14 at 9 p.m. ET and features exclusive interviews with Brittanee Drexel's family and friends, investigators and other key figures involved in the case.

Moody was charged with obstructing justice, kidnapping, criminal sexual conduct and murder.

"I will never forgive him for what he did to my daughter," Drexel said.

Dawn Drexel said she didn't know that her daughter had gone down to Myrtle Beach until she heard from her daughter's boyfriend, John, a few days later.

John did not travel with Brittanee Drexel to Myrtle Beach, but kept in constant contact with her, text messaging his girlfriend during her trip until their text message exchanges abruptly stopped on April 25, according to Drexel.

Investigators said they tracked Brittanee Drexel's cellphone pings to a location nearly 50 miles south of where she was staying, in a rural, swampy area.

Despite searching the dense and desolate Lowcountry swamp extensively on horseback, ATV and foot, investigators came up empty-handed.

"I knew she was somewhere out there, but you know just thinking, 'Oh my God. Are we ever going to find her?'" Drexel said.

In 2011, investigators conducted a search at a motel in Georgetown, South Carolina where Raymond Moody, a registered sex offender, had been staying at the time of Brittanee Drexel’s disappearance.

Moody had returned to his hometown of Georgetown, South Carolina after being convicted and serving approximately half of his 40-year sentence in California for multiple sexual assaults.

Police had identified Moody through the local sex offender registry. Moody had also been pulled over for a traffic violation near Myrtle Beach the day after Brittanee Drexel vanished.

Though the search of the motel produced no evidence that could connect Moody to Brittanee Drexel, details from the pullover provided clues. At the time of that traffic stop, Moody had scratches on his face, according to Chuck Capp, a retired Myrtle Beach police lieutenant who was involved in the investigation.

In an exclusive interview with "20/20," Ernest Merchant, a former romantic partner of Raymond Moody, says a couple of days after Brittanee Drexel had gone missing Moody showed up at his home unexpectedly.

“I saw that his face had claw marks all over it,” said Merchant. “His neck, cheeks. He had a shaved bald head. His head were just clawed.” added Merchant, recalling his encounter with Moody.

But the police would not fully understand the connection until years later.

While authorities have not released many details about what led them to now charge Moody, Brittanee Drexel’s family said authorities told them that investigators had obtained new evidence via enhanced surveillance video and cellphone data.

“I think it was a lot of the cell phone data, because they could place [Moody] at the same time, same location as Brittanee's cell phone,” said Dawn Drexel.

Solicitor Jimmy Richardson, the district attorney on the case, told ABC’s Charleston affiliate WCIV media that video captured the car Moody was allegedly driving the night of Brittanee Drexel’s disappearance.

Dawn Drexel told "20/20" she was shocked when she learned that Moody was in custody.

"I go, 'You've got to be kidding me,'" she said, realizing that Moody had been identified as a person of interest back in 2011.

Solicitor Richardson told WCIV that he believed Brittanee Drexel got willingly into Moody's vehicle, but that soon after it turned into a kidnapping.

In Drexel’s mind, her daughter, who did not like walking, might have been hoping for a ride back to her hotel the night she vanished.

"When they drove past the hotel, she was probably like...I'm in trouble. I couldn't imagine how scared she was,” said Drexel.

Richardson told WCIV that Moody allegedly took Brittanee Drexel to a boatyard landing on the Santee River, where he raped and murdered her, and then allegedly buried her body a few miles away in a wooded area in Georgetown County.

In May, the day law enforcement held a press conference announcing Moody’s arrest, her family was taken to the site where her remains were found. Brittanee Drexel’s remains were positively identified through her dental records.

"I think I went numb again and I was just so angry," Dawn Drexel said.

Brittanee Drexel’s brother drew a heart and Brittanee’s soccer jersey number in the dirt where his sister’s body had been buried.

“Just standing over where she was...it is very hard for me,” said Camdyn Drexel. “But it gave me closure.”

Brittanee Drexel's father, John Kahyaohlu, told "20/20" that there is still an emptiness in their hearts.

"There's no such thing as closure. We have to live with this for the rest of our lives. We have to learn how to live with it," he said.

Brittanee Drexel’s mother believes that Moody should never have been let out of prison on his prior convictions and is hoping to have her day in court to confront her daughter’s alleged killer.

"My mom was destined to find my sister from day one,” said Myrissa Drexel, Brittanee's sister, in an exclusive interview with 20/20. “ But we're just waiting for justice for her now.”

Moody has a hearing scheduled for next Wednesday, Oct. 19. He has not entered a plea yet.

"To be honest with you, I hope he rots in hell," Dawn Drexel told "20/20."