A 16-year-old Georgia girl, smart beyond her years, with dreams of going into medicine. That is, until she goes missing. And she won't be the only one that vanishes that day.

Gone without a trace: A sweet-sixteen Georgia girl has vanished into the dark night along with her stepfather.

A mother's desperate plea for help; an intense police investigation soon digs deep into the murky mystery. Will they recover Janell and Leon?

One shocking revelation will surface, and it will paralyze a Georgia community already on edge.

The day had been so joyful for Latania Janell Carwell, simply known as "Janell."

"Janell was a loving, very intelligent, smart young woman who wanted to be a doctor, who was an honor student," said family friend Pastor Angela Harden.

Janell was turning 16.

"That was the morning of her 16th birthday," said Richmond County, Georgia Sheriff Richard Roundtree.

It's Easter Sunday 2017. She celebrates the holiday and her birthday with family and friends. Neighbors say the young teen seems happy.

"She had not been reporting any problems to anyone," said Sheriff Roundtree. "The neighbors saw nothing. They were having a cookout. She was inviting friends over. So it was nothing for us to suspect that there was something going on."

But shortly after midnight, something does go on. And a birthday celebration is about take a strange and tragic turn.

Janell's mother Tanya Tripp calls 911.

"Yes, ma'am, um, I was calling to report a missing person," Tanya Tripp says on the recorded call. "I pray to God that they're not [inaudible]. It's not like them not to answer the phone."

Tanya says it's not just her daughter who's vanished.

911 Dispatch: "Your husband and your daughter are missing?"

Tanya Tripp: "Right."

Tanya tells police her 38-year-old husband Leon Tripp, Janell's stepfather, is not answering her now-frantic calls. Neither is Janell.

Tripp: "I've been calling and texting."

911 Dispatch: "They're not answering?"

Tripp: "Neither one. And that's not like neither one of them because they see me calling, they're gonna answer."

As Tanya reveals more, cops soon discover the teen and her stepdad have been missing for nearly 24 hours. Tanya soon tells the dispatcher the pair had left the house together in the midnight hours the day before.

"Her husband had received a call from a friend who had broken down and they were going to render him assistance," said Sheriff Roundtree.

Tanya says Leon hopped in his truck, heading a half-hour's drive away from Augusta to Clarks Hill, South Carolina to help his stranded friend. She says he took her phone with him.

Tripp: "His cellphone don't have a map on it where you get directions or whatever, so he got my cellphone."

At first, Tanya says, she didn't even realize Leon took Janell with him. Then she tells police her tech-savvy daughter went along to help work the GPS on a smartphone.

Now, both Leon and Janell have disappeared.

"There was nothing ominous about it at first," said Sheriff Roundtree. "She was supposed to be in the company of a trusted adult, which was supposed to be her stepfather."

"What stepdad wants for his daughter to go with him to help another guy at one o clock in the morning?" said Pastor Angela Harden.

The mystery stunned Augusta, Georgia, says Angela Harden, a local pastor, community activist and radio talk-show host, raising suspicions and fears.

"You want to make sure that that child is getting proper rest, sleep, and you wouldn't allow them to go at that time of morning to help someone that's broken down," said Pastor Harden. "That doesn't make sense."

But despite what some questioned as bizarre circumstances, at the moment, loved ones focused down on one thing: finding Janell and Leon.

Two weeks later, the high school student and her stepdad are still missing.

Pastor Harden soon takes to social media, pleading for clues, going live on Facebook with Janell's mom Tanya. Tanya tells viewers that sickness from brain cancer and lung cancer prevented her from riding along with Leon the night he went missing with Janell.

"I was inhaling too much of the smoke, so my husband told me to go in the house and lay down, so I did, 'cause I couldn't breathe," Tanya said in a Facebook Live broadcast. "And 3, 4, 5, 6 o'clock, I'm calling, texting. Nothing.

"I need my baby home, like 15 days ago-type home, 'cause she has never been away from me this long," Tanya said in the broadcast.

The plea is an effort to raise money for a reward offered to anyone who knows something. The well-wishes and donations begin to pour in.

Police are doing their own searching for clues. And they soon catch their first break: They spot the white pickup truck in which Leon and Janell were driving abandoned along the road just a mile from their home.

"We processed the truck to make sure if there wasn't any trace evidence, any physical evidence, DNA or anything of that nature, that showed signs of a struggle or something had happened, and we found none," said Sheriff Richard Roundtree.

If the truck turned up in the neighborhood, is there a chance Janelle and Leon will too? Cops step up their search, hoping cellphones will provide some footprints -- and answers.

"What we did was based on her cellphone and his cellphone records to try to triangulate the area in which both phones were hitting off the same towers," said Sheriff Roundtree. "Based on those tower readings none of it suggested that they were in the Clark Hill area as he originally had stated."

Janell and Leon never make it to that area where Leon says his buddy is stranded. And that's not the only troubling find.

"Prior to her missing, we were able to track phone records and her social media activities, so she was very active, and all that had ceased," said Sheriff Roundtree. "With the digital footprint of a 16-year-old just to evaporate, that was extremely strange."

And then, a number of new tips coming into police take the case in any even more bizarre direction. People say they've actually seen Leon Tripp, more than a hundred miles away in Atlanta -- without Janell.

"He had briefly stayed with certain friends in Atlanta," said Sheriff Roundtree.

"The stepfather was spotted in a location without the presence of the daughter," said Richmond County Sheriff Richard Roundtree. "He had a relationship with individuals in Atlanta. He had friends. He actually made two or three trips back and forth while we were actively looking for him and the daughter."

Detectives set out to track Leon down. But first they dig into his background to find out just who they're dealing with.

"Leon Tripp was in prison. He had some assault charges, he had some cruelty to children charges," said Sheriff Roundtree.

Investigators soon discover that when Leon met Tanya, he was behind bars doing time for aggravated assault. Leon and Tanya corresponded with one another and struck up a relationship. They even got married while Leon was in prison and made future plans.

"He actually was released and moved directly into the family home," said Sheriff Roundtree.

The family home -- with Tanya, Janell and Janell's little sister.

"Tanya Tripp should have protected Janell from the very beginning, two years ago, when she met him," said Pastor Angela Harden.

But now Janell is gone. After several sightings of Leon and a whole lot of unanswered questions about Janell's whereabouts, Leon is wanted again. Officers get a warrant for his arrest on kidnapping charges. But as they search, Leon's wife Tanya seems torn.

"She did show concern for her daughter," said local TV reporter Kelly Wiley. "But when I asked her, 'Hey, investigators believe that he's taken her,' she was very defensive."

Kelly Wiley covered the story extensively for WRDW News 12 and WAGT 26, and interviewed Janell's mother.

"The community really felt for Tanya Tripp," said Wiley. "They saw a grieving mother who wanted to know where her child was."

Investigators say they also began noticing Tanya Tripp's strange behavior.

"She even went on the media speaking out against the sheriff's office saying we were wrong and we were falsely accusing her husband," said Sheriff Roundtree.

Undaunted, U.S. marshals go searching for Leon Tripp in Atlanta and reportedly discover he's at a U-Haul facility. When officers corner him there, he's not alone. Right by his side is Janell's mom, Tanya Tripp.

"We were extremely shocked when we found her and him actually together," said Sheriff Roundtree. "And that's when we really got that sick feeling that, you know, this case is really not heading in a good direction."

Tanya had an explanation. She tells cops it was by sheer accident that she and Leon were discovered together.

"Tanya Tripp was pretty much sticking with her story, and that when she was traveling to Atlanta she had just seen him walking along the road and it was just a big coincidence that they had found each other," said Kelly Wiley.

Authorities slap Leon with kidnapping charges. And not buying Tanya's story, investigators charge her with hindering the apprehension of a criminal.

Those who know the family well are stunned. Neighbor Ernestine Howard says Tanya called her from jail to tell her the news.

"I asked her 'What in the world?' I said 'Tanya, please tell me that's not true. Are you serious?' And she said yes," said neighbor Ernestine Howard.

But just how involved is Tanya Tripp in her own daughter's disappearance?

"That's the $64,000 question," said Sheriff Roundtree. "The mother gave several interview accounts, but each story was inconsistent. But they were telling a little bit more about their deal, that they were trying to paint another picture."

One of those stories, referenced on the 911 call: Leon, leaving in the middle of the night to Clarks Hill, South Carolina to help a stranded friend, and taking Janell with him to work the GPS.

But as police press Leon, his version slips into something completely different. Leon tells police that he and his stepdaughter actually were headed to Atlanta.

"He gave her some money in which to get on the bus and come back to Augusta and he hadn't seen her since," said Sheriff Roundtree.

When investigators grill Tanya about Leon's version, the normally talkative mother suddenly gets tongue-tied.

"Come to find out that she only had that initial story. She never prepared for the follow-ups," said Sheriff Roundtree.

Cops soon look back to the original 911 call, which may hold hidden clues to Janell's mysterious disappearance.

"It wasn't an alarming call until you go back and put all the pieces together," said Sheriff Roundtree.

That first piece of the puzzle begins with Tanya's seemingly frantic 911 call the night after her daughter goes missing.

Tanya Tripp: "I've been calling and texting and leaving messages and nothing."

911 Dispatcher: "They're not answering?"

Tanya Tripp: "At all. Neither one."

But police say Tanya's emergency call is one big well-rehearsed lie.

911 Dispatcher: "OK ma'am, as I'm talking to you, we have a deputy en route to you."

Tanya Tripp: "OK."

"We truly believe that the mother knew that we would never find the child where she said where to look for her," said Sheriff Roundtree.

And Roundtree claims Tanya was hiding another dirty secret. Remember she claimed to be battling cancer? He says that's not true either.

"The mother was complicit in this criminal act," said Roundtree.

Cops say cellphone records show Leon and Janell were never in the area Tanya claimed they drove to. They now believe Tanya made it all up to buy time. When Leon was arrested, Sheriff Roundtree claims, he was interviewed.

"It led us to believe that we were now working a homicide investigation," said Roundtree.

According to prosecutors, since that interview, Leon provided a statement to them saying Janell is no longer alive.

"We no longer consider this a missing-persons investigation," said Roundtree in a news conference.

UPDATE March 23, 2018:

Sadly, just days ago, the sheriff's words would prove to be tragically prophetic.

"We received a phone call from a citizen that they were surveying the back yard of a residence and had discovered what they believed to be human remains."

The tireless yearlong search for the sweet 16-year-old came to a heartbreaking end after a homeowner in Augusta found a bone sticking up from a shallow grave in the back yard of a vacant house.

Investigators confirmed they are the remains of 16-year-old Janell Carwell.

The coroner was quickly able to get positive identification from dental records because Janell had gone to the dentist just days before she disappeared.

Now that Janell's body has been discovered, both her mother Tanya and stepfather Leon Tripp have been charged with murder. Leon Tripp is also now facing several other charges including kidnapping with bodily injury, cruelty to children in the first degree. Tripp and Janell's mother Tanya are both also charged with concealing Janell's death,

Public defenders are representing Leon and Tanya Tripp. Neither has yet to enter a plea

As prosecutors work on building their case, they have not revealed a motive for Janell's murder, leaving the community of Augusta, Georgia wondering why, and how, this could happen to a sweet 16-year-old girl.

The district attorney says because of the cruel nature of this alleged crime, she will go for the death penalty in Leon Tripp's case.

Deputies say it could take a few weeks for the autopsy to be finished before they can determine Janell's exact cause of death.