A young girl preparing for Christmas Day goes to bed like normal. But in the morning she's gone.

We want to warn you that the details of this today will be difficult for any parent.

One moment Sarah Foxwell was seen at her home, and the next moment she was gone, a beautiful 11-year-old girl snatched from her own bed in the middle of the night.

Sweet Sarah Haley Foxwell was nicknamed "Haley Bug" by her family.

"When she hit that age 11 she was like my name is Sarah, not Haley Bug,'" said Jennifer Foxwell, Sarah's mother.

Sarah's outspoken, a shining star in her 6th grade class in Salisbury, Maryland.

"She comes from a family of nine children, and she was right there, smack in the middle, and she was the one that was the referee, the lover, the hugger, the one that always had a smile, no matter how bad her day was, she always had a smile," said Jennifer Foxwell.

And many days were rough for the Foxwell family. As a single parent, Jennifer was struggling to make it, so Sarah and her siblings were temporarily staying with Jennifer's dad and her sister Amy at a converted barn house. But Jennifer was working overtime, determined to make this the perfect Christmas for all of her kids.

December 22, 2009. As the sun goes down, the temperature dips below freezing, and snow falling outside guarantees a white Christmas.

"They were running around the house, goofing off. They had pizza the night before," Jennifer said.

Around 9 p.m., Sarah and her 6-year-old sister Emma playfully skip off to bed. The girls share a room at the end of a long hall, right next to the back door. That sweet moment shared by the sisters now haunts Jennifer.

Just 10 hours later, Jennifer received a disturbing call from her sister Amy.

"She said 'Sarah's not in her room. Her shoes are here, her jacket's here. She's not in the house, she's not outside the house. We don't know where she is at,'" said Jennifer Foxwell. "There was snow on the ground. It was 25 degrees outside. I knew immediately something was wrong."

Sarah's family calls the sheriff's department immediately. Wicomico County Sheriff Mike Lewis and Sergeant David Owens and the entire sheriff's department descend on the old barn house, terrified they have a kidnapping on their hands.

"Every sheriff's deputy at this office came back to work. They did not want to spend Christmas with their families while this little girl was still missing," said Sheriff Lewis.

In the chaos, Sheriff Lewis made a promise to the distraught mom.

"He puts his arm around me and he says 'I want you to know that I will do everything in my power to bring her home to you,' and I looked at him and I said 'I'm going to hold you to that,'" said Jennifer.

With less than 48 hours before Christmas, they begin desperately searching for Sarah. They were looking inside the house and outside the house, whether or not somebody broke in, but there was no forced entry. The front door and all the windows were locked tight. But when cops checked the back door right next to the girls' room, they turned the handle and walked right in.

They also noticed Sarah's green toothbrush was missing from the bathroom. And there was one thing no one could explain.

"The dog didn't even bark," said Jennifer.

Then Sarah's Aunt Amy suddenly remembers a key hidden outside for emergencies.

But when she went to look for that key, it was missing, and little Sarah's family now knows she's in big trouble. The sheriff's office immediately issues a statewide Amber Alert. Sarah has without a doubt been abducted.

Whoever took Sarah knew about the key. The kidnapper was someone that knew them, and where Sarah was sleeping.

Then out of the shadows a frightened little voice confirms their nightmare: Sarah's 6-year-old sister Emma says she has a secret to tell.

"Emma is telling them somebody took her. And she knew him," said Jennifer Foxwell.

The family dog never barked, and the 11-year-old's green toothbrush is missing. Their worst fears are confirmed by Sarah's terrified little sister Emma. She tugs on her grandma's nightgown, looks up and blurts out, "I saw the man who took Sarah."

"What he was wearing, what he looked like, everything," said Jennifer Foxwell, Sarah's mother. "She was 6, and she knew him."

The 6-year-old pretended to be asleep, but instead watched and listened to every sickening thing the monster said to her big sister.

What did he say to her?

"Emma has not disclosed that yet," said Jennifer. "But she was able to identify him because she knew him."

She knew him? The hair suddenly stands up on the back of everyone's neck

"Emma pulled my mother aside and told my mother that 'Tommy took her,' and my mom was like 'What do you mean?'" said Jennifer.

"Tommy" is Thomas Leggs Jr. He's Aunt Amy's former boyfriend, and he is no stranger to the Wicomico Sheriff's Department either.

"Thomas Leggs is a predator. A predator of young girls," said Wicomico County Sheriff's Sgt. David Owens.

Investigators pull up his rap sheet, and their hearts sink. The 30-year-old has a long history of molesting girls.

"He defines the worst of a sex-offender," said Sgt. Owens.

And this guy has already done hard time. Thomas Leggs Jr. had been sentenced to seven years in prison for the 4th-degree rape of a teenager, and served six months for a 3rd-degree sex offense involving a child.

And just a few months before kidnapping Sarah, Leggs was arrested again. This time for assaulting a young woman. That attack was eerily similar to Sarah's.

"He crawled through her window in the middle of the night and she woke up and saw him standing there with his clothing on the floor committing a sexual act while watching her sleep," said Sheriff Lewis. "This is the kind of guy we were dealing with."

He was out on bond when this happened to Sarah.

The sheriff says when he met Sarah's Aunt Amy, she had no idea she was opening the door to a monster.

"Sometime early in that relationship she had recognized that he was a registered sex-offender, and so in true fashion for a seasoned sex-offender, he was able to convince her he wasn't a bad guy," said Sgt. David Owens. "That 'He was OK, it was just some things that had caused him to have to be there, but it wasn't a big deal.' She allowed that to become her belief system. There came a point in time that he was in the house on a regular basis."

During those visits cops say Leggs became disturbingly close to young Sarah.

"Something about Sarah fancied him," said Sgt. Owens.

Cops say the predator started planning his sick attack.

"I absolutely think he was plotting," said Owens. "It was all ripe for the picking. He knew how to access the house. He knew where the hide-a-key was. This night in question just became the night that I guess he was ready.

"He went straight to her bedroom," said Owens. "Sarah knew him and he had become, unfortunately, a trusted person in the home. He was obsessed with Sarah as his target."

Frantic deputies track down Leggs to a shed where he lived on his parent's property.

"We searched his shed," said Sgt. Owens. "It was full of pornographic magazines and pornographic videos. It just makes your skin crawl."

There's no sign of Sarah, but based on her 6-year-old sister's positive identification, sheriff's deputies haul Leggs in for questioning. For the next several hours, they interrogated him.

"Denial, denial, denial," said Owens.

"We all seemed to get along great," Leggs says in the recorded interrogation. "I try to be very cautious around the younger girls because of my past and everything else, just so there's no mistakes. I don't be alone with them or anything like that. And which, if you talk to Amy, she should be able to confirm that I was never alone with them whenever we were together."

When asked why Emma would point the finger at him, Leggs actually claims the 6-year-old was a troublemaker.

"Amy said she was a little handful and stuff, and she said a couple of things she'd done," Leggs says in the interrogation. "She'd do little odd things."

"I knew within a few minutes that he had definitely committed the crime," said Sheriff Lewis. "The way he snickered and smiled at my detectives, it was clear that he thought that he had committed the perfect crime."

There's just one problem: Leggs tells detectives he has an ironclad alibi. Police verify Leggs was indeed with a friend at a local bar -- but there's a gaping hole in his story: No one, including his parents, can confirm his whereabouts between 1 and 7 o'clock that morning, the time Sarah went missing.

"We had our man. We were just going to have to prove it," said Sheriff Mike Lewis.

And they are about to. Proof was in Leggs' gold pickup truck. Right there on the floorboard was Sarah's green toothbrush. But where was Sarah?

"Everyone hung on to hope that we could save her life," said Sgt. Owens.

Sarah's missing green toothbrush is found in Leggs' pickup truck. The tire marks in the snow near the family house from that night match his truck. And then cops make a discovery so vile it makes prosecutor Abby Marsh's blood boil.

"He still had on the same underwear," said Abby Marsh, deputy state attorney of Maryland. "And there was DNA evidence that was retrieved from the underwear that linked to Sarah."

Now authorities know without a doubt, they have their man. But still there's no sign of Sarah.

Cops still had hope of finding Sarah alive. Even though Thomas Leggs had a history of assaulting and molesting young girls, he had never murdered any of his victims.

Cops are holding on to hope for a Christmas miracle. Dedicated officers from all over the state worked straight through the holiday. Boots on the ground and dive teams brave freezing temperatures. Cops desperately needed a break.

"We're working feverishly through cellphone records to try to determine path of travel," said Sgt. Owens.

And then they get it. In the wee hours of the morning when Sarah disappeared, Leggs' phone pinged off of three different cellphone towers.

"Because there were three towers they actually were able to do an intersection of those towers and triangulate an area," said Marsh.

Authorities believe Sarah is somewhere in that triangle-shaped piece of land.

"We knew what the cellphone data was telling us," said Sgt. Owens. "We knew that we were going to be in the ballpark Christmas Day."

As the sun rises that Christmas morning in 2009, cops zero in on that slice of land, with a sliver of hope in their hearts.

"We all tried to have Christmas morning," said Sgt. Owens. "I remember being told 'You're not worth anything to us, you need to go back to work.' And we knew we were going to find her that day."

And law enforcement is not searching alone. On that Christmas Day everyone from everyone from homeowners to hunters joined the search for Sarah Foxwell with the hope she was still alive. There were thousands of people on Christmas morning.

"It literally took my breath away," said Sarah's mother Jennifer. "They didn't care that it was freezing. They didn't care that they had Christmas with their families."

The 3,000-man civilian cavalry was so big the sheriff had to use the local baseball stadium as a command post.

"I pleaded to everyone, once you went out and searched your property, just tie a yellow ribbon around your mailbox, and when i went on another helicopter flight after I did that, our community was littered with yellow ribbons everywhere," said Sheriff Mike Lewis.

Tragically, there would be no Christmas miracle.

"She was lying on her back with her little arms reached out to the sky, to heaven," said Lewis. "That's how she was found."

"I was like 'Thank God, we found her,' but when I saw her and what he had done to her, and when I saw what was left of her, it was Christmas Day," said Lewis. "That was our Christmas. It was tough. It just hurt us all, and I felt like we had failed."

"I walked in the dining room and Mike and David Owen pretty much told me what happened. They found her body," said Jennifer Foxwell.

"He attacked her. He sexually attacked her," said Sgt. Owens. "What that child went through in the last hours of her life are horrific. He tried to choke her, tried to drown her in a mud puddle. The reason we know he tried to drown her in a mud puddle is because of debris from the mud puddle was in her lungs. He left, got gasoline, came back, poured gasoline on her body."

Was she still alive?

"He didn't think so. But he lit her on fire. The autopsy showed that she inhaled the smoke. So yes she was still alive," said Owens.

Thomas Leggs Jr. is charged with the kidnapping and murder of Sarah Foxwell.

"If there was ever a case that screamed for the death penalty, it was this case," said Sheriff Lewis. "It was the brutal kidnapping and brutal murder and brutal destruction of this little girl's body that screamed for the death penalty. This man deserved to die."

For prosecutor Abby Marsh, Leggs' case was also personal.

"I was the prosecutor in his first adult sex offense that was charged," said Marsh. Leggs was sentenced to seven years, but tragically for little Sarah, he was let out early, paroled after just six months for good behavior.

"He shouldn't have been out of jail," said prosecutor Marsh. "If he had remained incarcerated Sarah might be alive."

Marsh wanted to make sure this would never happen again. In Sarah's case the state of Maryland would seek the death penalty. But before the case would go to trial, Leggs cut a deal: In exchange for his life, Leggs pleaded guilty to every charge and was sentenced to life behind bars.

"I believe that justice was served," said Abby Marsh. "The main thing for me is he will never be able to hurt another child again."

"I know she's at peace," Jennifer Foxwell says about her daughter Sarah.

Emma, the brave little 6-year-old, who helped cops catch her sisters killer is now a teenager. She still watches over her big sister at her grave.

"She doesn't really talk a lot when we're out here," said Jennifer. "But I expect that.

"I know we'll never get her back," said Jennifer. "I know Sarah is gone forever, but I really want to somehow make a difference so that no other child has to go through that."

The little girl once nicknamed "Haley Bug" is now considered a Christmas angel here. Sarah Foxwell's legacy will serve to protect other children through "Sarah's Law." It mandates all child-sex-offenders in Maryland serve a minimum of 15 years without the possibility of parole.

"She's everywhere. I don't think anybody will forget her," said Jennifer.

Just days after entering prison, Leggs was attacked by a fellow inmate in the dining hall. He was slashed three times in the head, neck and hand. Those injuries however were not very serious.