A young college student is reported missing by her fiancé. And something doesn't sit right. Her keys and her purse are still in the house.

It's two days before art student Katelyn Markham's 22nd birthday. But sadly, she will never celebrate it.

It's been 18 hours since John Carter says he last saw his fiancée, Katelyn Markham, alive, on August 14, 2011.

Panicked, Carter calls his future father-in-law, David Markham. David races to his daughter's place. He's met there by Fairfield Police Detective Rebecca Ervin.

"When we got to Katelyn's condo, there was no sign of forced entry into the town home," said Det. Ervin. "We checked the doors, checked the windows, checked everywhere. Nothing that's jumping out. There wasn't anything forced or broken. There's no sign of a struggle."

Inside Katelyn's bedroom Fairfield Police investigators discover Katelyn's purse and car keys laying in the center of her bed. Also in the bedroom was her dog, who had been locked in. That was unusual. Fairfield Police agree.

Katelyn was graduating from art school, engaged, and getting ready to move to Colorado with her fiancé.

Her fiance, John Carter, who was the last known person to see her alive, breaks down his final moments with Katelyn to detectives.

Katelyn's best friend, Michelle Feist, claims that just two days before Katelyn went missing, the couple had been fighting about money and the heated disagreement came to a head at a church festival. Michelle says Katelyn left the festival early because she was so upset. Two days later, Katelyn was gone.

Twenty heartbreaking months pass -- then a break in the case.

Twenty-five miles away, in Indiana, skeletal remains are found covered with trash in an area known for dumping. Crime scene investigators brush away debris to reveal several bones, including a skull and jawbone.

"When we looked at the picture of her missing report, we could almost identify her directly from her teeth," said Indiana State Police Detective Vance Patton.

The local forensic anthropologist positively identified the remains as belonging to Katelyn Markham.

But how in the world did Katelyn end up dead in trash heap in Indiana?

Residents in the small town of Fairfield, Ohio are desperate for answers when an anonymous donor with no connection to the case who has a keen interest in finding justice in unsolved mysteries, makes a huge donation. That money brings in private investigator J. Ryan Green.

"He's an individual that wanted to do something nice for somebody before he died, is what he told me, felt like Katelyn needed an outside investigator to come in and take a fresh look at the case," said Green.

Private investigator J. Ryan Green jumps goes back to the beginning: The 911 call made by Katelyn's fiancé, John Carter, on the night she went missing. John told the 911 operator that Katelyn's car and purse are at her home, yet when the 911 operator asks if he's there, he says he's on his way. Green wonders, how would Carter know about her car and purse if he wasn't even there yet?

"John misrepresented the truth in the 911 call with his own statements," said Green.

Adding to Green's suspicion, he says in police interviews, John claimed he went by Katelyn's house first, ran an errand, and then called 911. Green asks, Who does that?

Then Green calls a portion of John's 911 call into question. Carter says there was no argument, contradicting Katelyn's best friend Michelle, who claims she witnessed them arguing two days before Katelyn disappeared.

"I was a firefighter and a paramedic before I was a lawyer and I have heard my share of 911 calls," said Markham family attorney Tina Barrett. "I've made 911 calls and a 911 call is usually a call for help. That's what it is. Call for help. John Carter's call was a call to inform."

"And the Sacred Heart Festival is going on right up the street, and there's a lot of questionable people there," Carter says on the 911 call.

"He immediately offered up a theory," said Barrett. "You noticed an hour ago that your girlfriend isn't where she's supposed to be and the carnies took her? I mean that's a leap. That's a big leap unless you already know she's really gone. Unless you know she's dead. Unless you know she's lying in a garbage pit in Indiana."

Police say no one has been ruled out in this case as a person of interest. Katelyn's fiancé took a voice-stress analysis test, and that was reportedly inconclusive. He also took two polygraph tests, and authorities are not releasing those results. But private investigator Green believes where Katelyn's body was found is a huge piece of the puzzle.

"It troubles me a lot to know that you know the Carter family has property in this area and John knows this area," said Green. "This road is within close proximity to where John Carter would have traveled to go to his family's property."

The spot is just minutes away from John Carter's family home.

Police investigators believe Katelyn died in Ohio and her body was dumped in Indiana.

Green thinks the killer needed some help moving the body and has a theory.

"There was a friend at Katelyn's apartment besides John Carter, the last night she was seen, that friend left a little earlier than John did, supposedly," said Green.

Fairfield Police say the couple had company. A detective tells Crime Watch Daily it was a longtime childhood friend of John's named Brad von Bargen.

"Now he drove a car that he referred to as his baby, and I found out that he no longer had his baby," said Green. "He sold it in 2013 just after Katelyn was found, he sold it in a rush and said that he needed to leave to go to North Carolina."

The private investigator set out to find it, a 1997 green Acura that Green says Brad was driving the night he left Katelyn's home. He tracked it down.

Green reveals this all-new evidence only to Crime Watch Daily.

"I had it sent to police as a crime scene, they did a Luminol test, they saw there was blood evidence in the trunk area," said Green.

Unfortunately, this potential break in the case may have come too late.

"I obtained the vehicle almost four years later," said Green. "You have extreme cold in Cincinnati, and you have hot weather with the cleaning of the vehicle, shampooing. That messes with DNA, that messes with blood."

Despite what the private investigator thinks, the Fairfield Police Department tells Crime Watch Daily it does not believe Brad von Bargen was involved. But Detective Ervin says she can't officially clear anyone because this is an ongoing investigation. Green is still frustrated the car wasn't tested at the time of Katelyn's disappearance.

But the Green is not giving up. He gets his hands on another piece of vital evidence. It's never been released to the public until now: cellphone records from the night Katelyn went missing.

Green claims the cellphone timeline contradicts previous statements John Carter made to police. In recent months Carter hasn't been talking to authorities, but he agrees to meet with private investigator Green. And only Crime Watch Daily has hidden cameras set up and ready to roll.

John and his mother Karen, join investigator Green and his associate for the interview.

Green says the anonymous donor is no longer paying him, he plans to stay on the case for Katelyn's sake.

Anyone with information related to the case is urged to contact the Fairfield, Ohio Police Dept. at (513) 829 8201.