On Sunday, November 18, 2012, Dylan Redwine’s mother, Elaine Hall, drove him to the airport. Dylan was headed to Vallecito, Colorado, to visit his father, Mark Redwine, for Thankgiving. Dylan's mother had full custody of him following a bitter divorce, but Mark had visitation rights.

Mark picked Dylan up at the airport just before 6 P.M. that evening. Surveillance footage captured Dylan on video at the Durango Airport, and later at a Walmart.

That night, Mark says that they ate dinner and watched a movie. “There was nothing out of the ordinary about that night,” he said in an exclusive interview with Investigation Discovery.

The next day, Dylan had plans to see a friend. Mark said that he got up at around 7:30 A.M. and went into town to run some errands. “I thought that he was going to get up with me when I left to go into town that morning, but he wasn’t having no part of that,” Mark said.

Mark claims that when he left home, Dylan was still on the couch sleeping. After returning at around 11:30, Mark says he found the TV on, the door open, and a cereal bowl on the table. But there was no sign of Dylan.

Mark said that at first, he assumed that his son was out with one of his friends and just lost track of time. But after a few hours passed, Mark said that he became concerned. He got into his car and started driving around to Dylans’ friends houses. But none of them said that they had seen Dylan. His cell phone and backpack were not at Mark's house, and he was not answering his phone or responding to text messages.

Later that afternoon, Dylan's family reported him missing. “It was hard for me to comprehend what was going on,” Mark said. “I think I was in a state of shock or something.”

On Monday night, Dylan's older brother, Cory, and Elaine made the six-hour drive from Colorado Springs – and went straight to the police station.

Investigators pored over clues: The last time Dylan used his phone was at 9:37 on Monday night. His last text indicated that he made plans to meet his friend at 6:30 the next morning, but according to the friend, Dylan never showed up. His friend sent him a text message at 6:46 asking “where are you” and received no response.

Police considered the possibility that Dylan may have run away. After his parents’ bitter divorce, tensions ran high – and according to Cory and Elaine, Dylan was not looking forward to spending Thanksgiving at his father's house.

Search and rescue teams combed the area around his dad’s house with ATVs, mobile command centers, K-9 units, and drones. They scoured the woods, but found no trace of Dylan. As investigators continued to work the case, the family struggled to find answers: Did Dylan run away? Could he have been abducted? Or could the answers be found in someone closer to home?

Elaine criticized her ex-husband, saying that he did not help in the search effort. “He isn’t getting out and looking. Mark was sitting in his La-Z-Boy recliner watching TV," she told Investigation Discovery.

But Mark said, “As a parent, can you ever do enough to find a missing child? And until that child is found, I don’t think anybody has done enough.”

Nine days after Dylan went missing, investigators announced that, given the length of time that had passed, police no longer believed that he had run away.

Investigators searched Mark's home and took him in for questioning. They said that they did not consider Mark a suspect and called the search “standard procedure." But Mark stated, “I believe that they thought that I was involved with kidnapping my son.”

Investigators took a portion of an area rug in Mark’s living room rug and seized his truck for processing. “I would have gladly allowed them to search my house without the search warrant,” Mark said.

Police gave both Mark and Elaine lie-detector tests. Elaine said that she passed with "flying colors." “All I have is law-enforcement’s word that I failed it miserably,” Mark explained.

In June 2013, investigators resumed their search for Dylan on Middle Mountain. Five days into the search, they found a terrible discovery just off the main road that winds into the mountain. Authorities found human remains including bone fragments and portions of a shirt. DNA testing confirmed that the remains belonged to Dylan. “My heart broke,” Mark said.

In August 2015, police announced that Dylan was murdered. They also identified a person of interest – Mark Redwine. Investigators explained that Mark was a person of interest due to his inconsistent behavior. “What exactly is a person of interest? Nobody can give me that answer,” Mark asked.

Cory claims that his father is capable of violence. But Mark has always denied any involvement in his son’s death, and says that he believes that the discovery of the remains were part of a set-up. “Either he was on that mountain and is still on that mountain, or Dylan was never on that mountain and the parts of him that were found were put there to incriminate me or to make me look guilty,” stated.

“Is it possible that if he was up getting away from things or whatever and wandered off into the woods far enough that somebody mistaked [sic] him for an animal and shot him?” Mark wondered. To support his theory, Mark has posted Facebook videos demonstrating how easy it is to climb up to the area where Dylan was found.

Dylan’s mother calls this idea “ludicrous,” pointing out that at the time Dylan disappeared, the mountain was about to close to hikers.

In November 2015, it was hikers who found Dylan’s skull a mile and a half away from where the rest of his body was found. Investigators were able to determine that his injuries were consistent with blunt-force trauma.

In July 2017, a grand jury handed down an indictment against Mark Redwine. He was charged with second-degree murder and child abuse resulting in death. The indictment revealed that investigators had found traces of Dylan’s blood in Mark’s residence.

Also according to the indictment, a cadaver dog alerted in the home, and in Mark’s truck. The indictment also stated that Dylan and Cory had both discovered compromising photos of their father, and that Dylan planned to confront him about them, according to The Denver Channel. According to Elaine, the photos allegedly showed Mark wearing women’s clothing with a soiled diaper in his mouth.

Mark denies that the person in the photos were him, and accused his ex-wife of Photoshopping him into the pictures in order to humiliate him.

In an interview that Mark did with Investigation Discovery prior to his arrest, Mark called Dylan the “love of his life” and insisted that he would never hurt him.

But Elaine disagrees. “I think he hurt Dylan, because if he couldn’t have him, no one else was going to,” she said. “He was all about ultimate revenge. That’s his mantra. That’s how he lives his life.”

Mark Redwine has pleaded not guilty on all charges. He remains behind bars in Colorado.

His trial is set to start on September 28, 2019.

For more on the case of Dylan Redwine, watch Investigation Discovery's Still A Mystery on ID GO!

Read more: The Denver Channel