She did exist. There really was a girl named Monique Daniels. And yet, but for a few of the people who knew her best, you'd never know it.

Did the 15-year-old run away? Does she want to be found? Or is the real truth hiding behind the very darkest of family secrets?

It's been more than two decades since anyone last saw her. The oldest of Chuck and Candyce Daniels' six children disappeared without a trace.

But before she became a ghost haunting old home movies, Monique "Nicky" Daniels was very much a part of her loved ones' lives.

One of Monique's best friends from school, who has asked to remain anonymous, remembers her as the kind of girl who always seemed to put others first.

Monique had big plans to become a doctor after high school. But she was also nursing her own wounds. The kind you can't see, but cut the deepest.

Allegations of abuse too horrific to repeat, all at the hands of the four oldest kids' biological father, a now convicted and imprisoned sex offender.

But soon after, Chuck and Candyce married and had two more children, and a new family portrait began to develop. Both parents were in the military, and according to Monique's sister Angelique Rameau, they ran their house like drill sergeants. Not necessarily the best fit for a teenage girl just starting to come into her own.

Monique got pregnant, and her parents were very upset about it. According to Angelique, her sister was forced to terminate a pregnancy. Then, one day not long after that, Monique suddenly wasn't there.

"She did run away from home," said Angelique. "My parents looked for her every single day. I remember the phone would ring, and somebody had seen her and they would jump in their vehicle and go try to chase her down."

"We knew where she was," said Monique's best friend, who did not want to be identified. "She was at a different friend's house and myself and one other guy called and talked her into going home."

But there would be no family reconciliation. Once back home, tensions were at an all-time high.

Just a few weeks before Monique's 16th birthday, Angelique, her oldest brother Brian, and her mom got an opportunity to tour with their church choir for a week.

After the trip, the three returned home to Moore, Oklahoma, back to where nothing would ever be the same.

"My stepdad said 'She's gone again,'" said Angelique. "And my mom goes 'Really?'

"Something was off. Something was wrong. The house was in a disarray," said Angelique. "We're talking about a spotless environment all the time. There were beer bottles, there were cigarette butts put out on the fireplace mantle. There was an empty pregnancy test, just the box, on the bathroom counter."

But far from being concerned, Angelique says her parents treated Monique's absence like just the next chapter in their "gone-again/off-again" relationship.

"I remember hearing, 'If Monique wanted to be here she would be,'" said Angelique.

Angelique says it wasn't long after the disappearance that Monique's parents seemed to be erasing all traces of her from their lives.

As the months wore on, Angelique says they were forbidden to talk about Monique.

But outside of the home, Monique's aunt, Leslie, Monique's mom's sister, was growing more concerned. She even offered to call in additional resources to help figure out what happened.

"She called my mom and was asking for the police report number so she could get Monique in the national database for Missing and Exploited Children and my mom said 'Yeah, I'll get that for you,'" said Angelique.

But that wasn't exactly true. Because what Aunt Leslie and the rest of the family were about to find out, was that there was no police report.

"I don't know what to think," said Moore Police Detective Terrance Coleman. "It definitely is suspicious."

Especially to Aunt Leslie. Though it put her at odds with her sister, she decided to take matters into her own hands.

"She called us and we started an investigation then, and a detective went and contacted Candyce at that time," said Coleman.

By then it had been about six months since Monique vanished, a gap in time loved ones feared would make it harder to find her.

Roughly six months after Monique disappeared, her sister Angelique got an apparent call from her long-lost sister.

"That night my mom called all the relatives and said Monique called and she's doing just fine," said Angelique.

And just a week after that call, the Daniels family also got a letter from Monique with a postmark from Dallas, nearly 200 miles away.

"She was married and had a baby named Chelsea," said Angelique. "They were currently living in Alaska but traveling around the country for his job, and she just wanted to drop a line and let mom know that she was OK."

Another letter soon followed, and it seemed like the mystery of Monique Daniels might finally be solved. But to some of Monique's relatives, like Angelique's aunt Leslie, something still felt off.

"My aunt has contacted the Moore Police Department, wants a handwriting specialist to check the authenticity of the letter," said Angelique. "Because she believed my mom wrote the letters."

Then, just a day before Monique's mom promised to take the letters in to be examined, there was a reported break-in at the Daniels' residence.

"The furniture was tipped over, there was some CDs missing, a couple little boomboxes, and the letters," said Angelique.

"The letters that were supposed to go to the police department that day for the handwriting specialist to check were missing," said Angelique.

But then, Angelique didn't need a specialist to convince her that there was no way her mom could've written those letters.

And the reason for that was because she wrote them. And that supposed phone call from Monique? Also fake.

"I wake up every day wishing that it didn't happen," said Angelique.

Angelique says her dad told her that after Monique left, her mom became suicidal.

"He said the only thing I can think of is what if we wrote letters saying that we were Monique so she'd feel better? And it did," said Angelique.

According to Angelique, her stepdad then said she faced jail time if she ever told. And with no letters, no Monique, and no one talking, the investigation had nowhere to go.

"I was scared. I was really afraid for myself and you know, I thought that I was going to be wherever she was, soon," said Angelique. "I thought he sent her away, because he threatened it to us so often, that he had places for girls like us. There were military schools for girls like us."

Angelique says after nearly two years of lies, cover-ups and the continuing mystery of what really happened to her sister, Angelique ran away and came to Michigan to be with family.

"I cried the entire way here," said Angelique. "On the way from the bus station to my aunt's house, I told her about the letters.

"She started to freak out. She said 'Oh my gosh, what has he done with her?' And it kind of dawned on me that he might have done something really bad to her, that it might not be just a military camp, that it might be way worse," said Angelique.

And she was about to get even more evidence she felt supported that theory, because when Angelique ran away, her parents filed a missing-persons report immediately, which, as the rest of the family was about to find out, was in very stark contrast to how they had reported Monique.

"He told the whole family that he had already filed a runaway report. That was not true. He lied," said Angelique.

Her parents never filed a missing-persons report on Monique until Angelique ran away from home almost 22 months later.

Authorities question both parents about the suspicious delay, and Chuck even admits to faking the letters with Angelique. But police make little headway.

"We never were given the opportunity for a lie detector," said Det. Coleman, despite police requesting one.

In addition, officers found a neighbor who claims he saw the girl get into a truck with a white male on the day she left.

True or not, Angelique was too scared to go back home, telling her aunt her parents were both mentally and physically abusive.

"The next day, went to Child Protective Services and I filed childhood-abuse charges against my parents," said Angelique. "My parents were trying to get me extradited back to Oklahoma, but the judge said no way. I found out later that they pled no contest to child abuse and neglect."

With Angelique now outside the home, and evidence of a cover-up out in the open, both she and her Aunt Leslie go public, appearing on various TV shows to discuss their suspicions surrounding Chuck and Candyce.

"Once they found out we had gone on 'A Current Affair,' they left the country and they went to Germany," said Angelique.

Officially, Chuck got a military transfer to a new base. But Angelique doesn't think it was a coincidence. Especially because of what Chuck and Candyce almost left behind.

"They brought all the kids up here and they were saying goodbye and my younger brother Andrew called me and said 'You gotta come and get me,'" said Angelique. "He was 13."

He was to be the third of the Daniels children to run away in as many years.

Like his sister, Andrew alleged abuse inside the home. And yet when his parents left to live in Germany for the next 10 years, he went with them.

Angelique continued living in Michigan, eventually got married, and over the next two decades, Monique Daniels became little more than a name attached to a phantom.

What would police say are the things that happened in this case that make it so difficult to investigate?

"The 18-month delay notification to the police department, combined with conflicting testimonies, and I mean, no body to indicate foul play," said Det. Coleman.

But a storm was gathering in the skies above Moore, an unstoppable force of nature that was about to bring old walls tumbling down. It was only a few weeks to the day since Monique had disappeared years earlier.

"An F-5 tornado ripped through Moore, Oklahoma, just trashing it, and I was watching it on TV, all these homes that I played in as a kid just obliterated, and the phone rings, and it's Andrew," said Angelique. "He's crying. I'm like 'What's going on? Are you OK?' And he said 'She wasn't talking,' and I said 'What do you mean she wasn't talking?' He's like, 'Ange, I was there, and she wasn't talking.'

"I knew he was talking about Monique and I knew he was about to tell me. And so I was quiet and I just listened," said Angelique.

It began, Andrew says, like a lot of days in the house, with fighting between Monique and her stepdad. Sometime later, Chuck gathered up the boys for a spontaneous fishing trip.

"Before we left, my dad was like, 'Hey, you guys need to go and say goodbye to Monique,'" said Andrew. "We all went in there in like a single file, I was in front, then my little brothers behind me, and Monique was in her room."

But Andrew says Chuck only allowed the boys to talk to Monique through her cracked bedroom door.

"When I saw Monique, she was on the floor in her bedroom, her legs were crossed. She was still," said Andrew.

After that, Andrew says, the boys left -- without their fishing poles, in the pouring rain.

"We drove for two hours one way, and got off on an exit somewhere, and went to a McDonald's," said Andrew. "We got home, back to the house, and then my dad pulls the car into the garage.

"He goes inside the house, and leaves us in the car inside the garage, like an hour or more," said Andrew.

When Chuck finally let the brothers out, Andrew says he rushed to the bathroom, and got the eerie feeling he wasn't alone.

"I had a real eerie feeling in that bathroom that day, you know. I was actually like scared," said Andrew. "I hadn't seen Monique. The shower was closed. There's things that lead me to believe that she was in that bathtub."

Before he could check, Andrew says Chuck hustled all of the boys into his bedroom. Then, after telling them he was going to go look for Monique, he locked them in -- for two days.

"After that I don't really remember much of what happened, meaning I don't recall the incidences after that," said Andrew.

But according to something Angelique heard from another brother, at some point while the boys were locked up, Chuck came back, then left with one of the twins.

"He said the only thing I can remember is being in the back of dad's truck and there was an oil barrel in the back," said Angelique. "That's all I remember."

In Angelique's mind, it was all pointing toward one very grim conclusion.

"I believe that Charles Daniels killed my sister Monique, and then I believe he put her in an oil drum and he drove her out to where he took her to and he buried her there," said Angelique.

Angelique isn't backing down. In fact, when Andrew first told her his story just a few years ago, she convinced him to go with her to the police. Officers even dug up the family's old back yard based on rumors Monique might be buried there.

"We didn't find anything," said Det. Coleman. "It's a missing persons case."

So what really happened to Monique Daniels? If she really did just run away, why did her parents wait nearly two years to report her missing?

And one of the biggest questions of all: What do Monique's parents think about their daughter's mysterious disappearance? Crime Watch Daily went to Tampa, Florida to ask them.

When I pressed Candyce about Angelique and Andrew's allegations, she did have this to say:

"Whatever happened, it's in God's hands. Thank you very much and I'm gonna ask now that you leave," Candyce said.

"And Angelique is a really messed-up young lady. Like I said, before you start taking and asking me about anything, you need to just I think leave the property before I call the police. Angelique is not a reliable source," said Candyce.

It was a dead end. But not long after that, another vehicle pulled into the driveway. It was Chuck Daniels.

"Did you check your sources with them? An alcoholic and a drug addict?" he said.

In response to that claim, Angelique acknowledges struggling with years of mental anguish, but denies any substance abuse problems. And while Andrew admits to having issues in the past, he says today he is completely clean and sober.

"Under advice of counsel, I have nothing to say to you. Angie, I love you. Sorry about that. Stay off my property," Chuck said.

What does he think happened to Monique?

"It's in God's hands. I don't know," Chuck said.

Neither parent has ever been charged or named as official suspects in Monique's disappearance. They wouldn't give us any real statement beyond saying that the matter is "in God's hands."

But there was one person willing to elaborate: one of the youngest of the Daniels boys, Charlie Junior, and he tells a substantially different story than Andrew.

"I think I was the last one to speak to Monique, and she was laying in her bed and she gave me a hug and said 'Have a good day, I'm sorry I'm sick, I can't go with you,'" said Charlie Jr. "She was fine."

But questions still remain. Like, why fake those letters after the girl's disappearance? Why hasn't anyone heard from her in so long? And what was in that oil drum? For now, the mystery continues.

"Maybe I am wrong," said Angelique. "Maybe I need to just move forward. Maybe I need to just let this all be in the past and you know, keep it hidden too. But I cannot do it. I have to let people know that there was a Monique Daniels."

If you know anything about the disappearance of Monique Daniels, submit a tip to Crime Watch Daily, or call or text our toll-free number anonymously at (844) 800-CRIME.