In a Crime Watch Daily exclusive, Ashley Reeves and Crime Watch Daily's Elizabeth Smart return to the scene of the crime.

It's the first time Ashley has been there since the day she was found. Ashley says she can barely remember the horror.

A criminal as callous as they come: Not only did he snap the neck of a 17-year-old and leave her for dead -- hours later he went out country line-dancing like nothing had happened.

Elizabeth Smart is in St. Louis with the disturbing details and the police video you have to see to believe.

It's the walk every policeman dreads: Deep into the dark woods in search of a body, led there by a suspected killer who's not only told them where to find his victim, but how he killed her.

Police cameras are rolling as the search party stalks through the tangled overgrowth to a clearing, and the body of 17-year-old Ashley Reeves. But in this shocking tale of terror, everything changes in the blink of an eye.

Before that horrific night in April 2006, Ashley Reeves was a funny and bright high school junior, an excellent student with a steady boyfriend named Jeremy Smith.

Ashley's younger sister Casey tells Elizabeth Smart that Ashley was the one she always looked up to.

But trouble would find Ashley on the horrible night she'd meet a monster in the woods.

It's a Thursday afternoon in April 2006. Ashley leaves her parents' house in Millstadt, Illinois for an appointment in Fairview Heights, a town almost 15 miles away for a job interview. She's driving an SUV belonging to her boyfriend. But that night Ashley wouldn't come home. Hours later, neither Ashley's family nor friends had heard from Ashley.

"Something was different with this case," said Swansea, Ill. Police Chief Steven Johnson. "This missing girl, Ashley Reeves, was not answering even texts from any of her friends. And one thing we know with young ladies is they will, maybe not answer their parents, but they will answer their friends."

Something's not right. Ashley's mom calls police in a panic.

"Unfortunately we get a few calls that are like that, and the vast majority of them are either, maybe they just stayed out too long with a friend or something like that, but there was something with her voice that really sounded very stressful, and I said 'Captain, this one sounds a little bit different, I think we probably need to run with this one right away,'" said St. Clair County Sheriff's Lt. Mike Hundelt.

"It wasn't too much longer after that, Ashley's car that she had been driving, was found at Laderman Park here in Belleville," said Hundelt.

Inside Jeremy Smith's abandoned SUV are Ashley's outfit for the job interview and basketball clothes. But there was no sign of Ashley.

Ashley's boyfriend Jeremy is a parent's dream: Wholesome, forthright, seemed to adore their daughter. They had been dating for nearly two years. But now investigators want to talk to him.

"When you start dealing with missing people you generally tend to focus on the people who are closest around them," said Hundelt.

Detectives put Smith in the hot seat. Smith tells detectives he was out of town the night Ashley went missing, and doesn't know a thing.

"He seemed like he cared for Ashley quite a bit," said Hundelt. "I had a strong feeling that he didn't really know anything that was going on."

But then the young man's interview yields a game-changing clue.

"She said 'I'm gonna go to this interview and I'm gonna go play basketball,'" Smith tells Hundelt in the interrogation.

"Why would a young female want to play basketball in a park far away from school?" said Capt. Johnson.

A friend tells police Ashley would often meet a man at a park to play ball, someone they all knew: 27-year-old Samson Shelton. Shelton is the driver's-education and physical-education instructor at a rival school. He's also an aspiring professional wrestler calling himself "The Teacher."

Were Sam and Ashley meeting up for more than basketball? Ashley's boyfriend tells detectives he doesn't think so.

But as Ashley's family continues their desperate search, a different story emerges.

Panicked parents decide to call every number from Ashley Reeves' phone bill after she goes missing. They come across a number they didn't recognize over and over again. They dial it, and on the other end of the phone, a former teacher, a man nine years her senior: Sam Shelton, a popular teacher and coach, who lives nearby with his mother and grandmother.

The night Ashley disappeared, the good ol' boy is caught on tape dancing at the Wild Country dance club.

"My mom actually talked to Sam that night," said Casey Reeves, Ashley's sister. "And he was like 'No, haven't heard from her, haven't seen her.' Hung up like it was no big deal."

But friends say Shelton is a big deal: Ashley told them she was romantically involved with the much-older man, and was supposed to meet him that afternoon.

"He was actually considered at the time a minor lead because what had been told to us was he was a friend of Ashley's, that they would just kind of play basketball together," said Lt. Hundelt.

Detectives pull the young coach right out of baseball practice for an interview. A very friendly and cooperative Shelton tells investigators that despite what Ashley had said, his relationship with the teen was purely platonic. He also says he's been dodging Ashley for days. He tells police Ashley was becoming obsessed with him, calling him non-stop.

"Starting off I felt like he knew more than what he was telling us," said Hundelt.

"I think he was going to try to just manipulate us, continue to talk to us and be cooperative and just kind of play along and hope that this will all just go away," said St. Clair County Sheriff's Sgt. Daniel Stockett.

But when pressed by police with statements from Ashley's friends, Shelton changes his story, telling cops their relationship went further than a goodbye hug -- a lot further.

"I will say this: we never kissed. We never kissed," Shelton says in the interrogation. "Yes, we did have sex in the back of the vehicle there, and after that day I felt absolutely terrible about that."

"Originally he had said they were friends," said Capt. Johnson. "And then he had said that they played basketball. And then he had said he wanted a relationship with her. And then he had said at one point he was trying to break off the relationship with her. He had changed the story so much that a person who didn't have anything to hide, why would you change it that much?"

"We just continued to catch him in lies, it was lie after lies," said Stockett.

Then a second bombshell explodes: Ashley Reeves was in Sam Shelton's car the day before. He tells police they had an argument and he left her by the side of the road. But Shelton's story ends with Reeves alive.

"She was screamin', kickin', everything," Shelton says in the interrogation. "Put her down, shut the door, ran the car, I took off. I left her. I left her there is what I did. I left her out there by Radio Range Road. I left her right out there."

Why was Shelton more concerned with line-dancing that night than with Ashley's well-being? His answer is as cold-blooded as it is unbelievable.

"I did not want to drive by there, because if I would've drove by there, if I would've seen her like, I don't know, if she had got hit by a car or something and she was laying over there in a ditch, if I would've seen that, I could not stand that," Shelton says in the recorded interrogation. "I have an absolute fear, I have a very weak stomach when it comes to, like gore movies, I can't even watch those. I still have in my head from that movie 'Texas Chainsaw Massacre' that came out, have you seen that movie? If I would like see her like laying on the side of the road right there, it just -- I don't know. I would have felt absolutely like horrible."

"You mean to tell me that this is a person that you cared for and that you left her on the side of the road, but you didn't even try to talk to her or call her after that?," said Hundelt. "I said 'I find that hard to believe.'"

The detectives hammer at Shelton's account for hours, but Shelton doesn't stray from his story.

Then, an unbelievable twist of fate: On a bathroom break, Shelton runs into the department's lead detective, Steven Johnson.

"He was an Explorer in our law-enforcement Explorer post. I was an adviser," said Johnson. "It's a part of the Boy Scouts, and they learn about law enforcement."

Johnson takes over the interview, looking for an angle that will break down Shelton's barriers.

"Tell us about the mistake that was made, Sam," Johnson says in the interrogation. Twenty minutes later Shelton crumbles at the mention of one name.

"If I left from here and I went and talked to grandma right now, and I laid down this whole story that you're saying, what's grandma going to say?" Johnson asks Shelton in the interrogation room.

"I just want to go home and I just want to explain to mom and grandma exactly what happened," Shelton replies.

Playing the "grandma card" may be the only way left to break Shelton and find Ashley Reeves. So Johnson doubles down on the heartache.

"Your grandma's not here," Johnson says in the interrogation. "Your mom's not here. But you know what? In a way they are. Because everything they taught you, all the talks grandma had with you, are within you. All of them are. And unfortunately right now, Sam, you ain't telling us the truth. And you need to. You have to. For mom. For grandma."

Johnson leaves the weeping Shelton alone in the interrogation room, just long enough for the guilt to sink in."

"When he asked to be alone, I knew he was ready to confess," said Johnson.

"Can I go show you what happened?" Shelton says in the recording. "I'd have to show you."

After more than 12 hours of grueling interrogation, 26-year-old Samson Shelton finally snaps, confessing to a despicable crime.

"I drug her to a wooded area, I tied this thing around her neck to make it look like someone choked her out there," Samson says in the recorded interrogation.

Now the guilt-ridden high school teacher agrees to take investigators to the hiding place deep in the woods where he dumped the body of Ashley Reeves. Shelton dragged Reeves far into the trees of a public park the previous afternoon. But now, under the cover of night and rain, Shelton can't get his bearings. Reeves' body could be anywhere.

"It was dark, it was rainy and it was cold and the woods were so thick," said Capt. Johnson.

"After we had walked through the woods for probably 20, 30 minutes or so, I was beginning to wonder if he was maybe just kind of taking us on a wild goose chase and kinda just playing with us again," said Lt. Hundelt.

Then, hearts stop as flashlights land on a grisly discovery: Ashley Reeves' broken body.

"She was laying on the ground on her back, obviously deceased," said Johnson.

"There was thousands of insect bites all over her," said Hundelt. "She had been out there for a long time." For 30 excruciating hours.

Then, a miracle: "She's breathing. She's breathing! Get EMTs!"

"I saw her chest rise and it was just like 'Oh my God,' we were just panicky," said Sgt. Stockett.

"Oh my God, we found her, she's alive," said Lt. Hundelt.

Emergency personnel race to save Ashley. She's been left for dead in the woods for more than 30 hours, cold, barely breathing, strangled nearly to death. Even though she's still alive, the prognosis is not good.

"The paramedics that were there told me that they didn't think she was going to make it out of the woods," said Capt. Johnson.

Back at the police station, evidence photos show Sam Shelton barely had a mark on him. When Johnson finally hears his confession he knows why: Ashley never had a chance to put up much of a fight.

"They got into some sort of an argument and she would not get out of his car, and he claims he got her into a wrestling chokehold, and when he did that he heard her neck pop," said Johnson. "And she went limp, and he didn't know what to do. He said that he panicked at that point."

Shelton describes what he did next. Be warned: His heartless confession will turn your stomach.

"I was a nervous wreck, thinking, 'What do I do? What do I do?'" Sam Shelton says in the recorded interrogation. "I wanted to make it look like she'd got she got strangled there in the woods."

"So he choked her. He choked her with his hands. That didn't work. She was still breathing," said Johnson.

"I took the belt and I pulled, I pulled it on her neck, I don't know how long I held on," Shelton says in the recording. "I had to turn my head 'cause I didn't want to see."

"All of a sudden I heard like a gurgle. And then all of a sudden when I heard the gurgle, I let go, and when I let go, she had spit, foam, coming out of her mouth. And then I'd seen that she was the sickest color I'd ever seen," Shelton says in the recorded confession. "Her tongue was like kind of protruding like that, between the teeth."

"He then used his foot for leverage to choke as hard as he could, and the belt broke," said Johnson. "So he repositioned one more time and choked until there was no more breathing, no more froth, no more changing of the facial color, and he left her in the middle of these woods."

"I just took off. I mean I literally darted through there like a bat out of hell," Shelton says in the recording.

Then, Shelton's confession concludes with this head-shaking exchange:

"Am I gonna be able to get like my contact solution and take my contacts out, and toothbrush?" Shelton asks during the interrogation.

"I don't think so."

"I can't take my contacts out?" Shelton says.

Reality has yet to sink in for this self-absorbed 26-year-old, who doesn't seem at all concerned about the girl he admittedly tried to strangle in the woods.

"Am I gonna get like a little private toilet? 'Cause I can't pee when there's people around 'cause of my urinary stress disorder," Shelton says in the recording.

"I don't know, Sam. I'll tell them that that's what you want, but I don't know if they'll be able to do that."

"Because I'll be miserable if I can't pee," Shelton says.

Samson Shelton is arrested and charged with attempted murder. Despite his confession, he makes bail and is release while awaiting trial. But his troubles with the law are far from over. At one point authorities say Shelton actually tried to commit suicide by ingesting a potentially fatal cocktail of prescription pills and alcohol. Then, when EMTs rush in to try to save him, the troubled teacher reportedly punches and spits at them.

"I was told by emergency room staff that he had some sort of writing on his chest, like a marker, that says 'Don't save me,' or 'Don't resuscitate me,' or something like that," said Chief Johnson.

Shelton pleads guilty to attempted first-degree murder and is sentenced to 20 years in prison.

But what about Ashley Reeves?

"She's tough. One of the toughest people that you would meet," said Johnson.

It's a toughness born out of a slow and grueling return from near-death.

"It took a while for her to come out of the coma. It took a while for her brain to wake up," said Casey Reeves, Ashley's sister. "Her brain was relapsing the incident over and over."

Months later Ashley regained full use of her body.

Now, in a Crime Watch Daily exclusive, Ashley Reeves and Crime Watch Daily's Elizabeth Smart return to the scene of the crime. It's the first time Ashley has been there since the day she was found. Ashley says she can barely remember the horror.

The one thing Ashley does remember is she was trying to break off the relationship with Shelton, and they got into a fight. Shelton told police he was trying to end it. Ashley would like to just forget that altogether.

"Part of me wants to try and remember, and then part of me is like 'Oh, that might not be a good idea,'" said Ashley.

The road to recovery has been long, painful and heartbreaking.

"They had to retrain me how to eat and how to drink," said Ashley. "But I remember my first drink of water, and it was amazing."

Ashley Reeves has never lost her will to survive.

"I'm a fighter and I just keep wanting to push myself harder and harder," Ashley said. "I've grown, gotten older and got a better outlook on life."

Today Ashley Reeves has a new life: Two kids, a job, a busy school schedule, and even an extended family that was formed the night she disappeared: The team of detectives that wouldn't let a madman get away with murder.

"Don't give up. Don't ever give up on yourself," said Ashley. "There's bigger, better things out there. I've gone through plenty of hardships, and it's just, just keep fighting. Every day it's a struggle, but you just gotta keep on trudging."