A major update on a missing-person turned murder case we've covered extensively here on Crime Watch Daily.

For years, police in Colorado have been investigating the death of 13-year-old Dylan Redwine. Now there's been an arrest.

A little boy lost? Or a heartbreaking case of murder?

It's a question many have asked ever since the morning 13-year-old Dylan Redwine vanished into the dark forests of Vallecito, Colorado. Now, what could be the appalling truth is beginning to emerge.

After five painful years, the man who grieved his son has the finger pointed at him in a stunning turn of events. Damning new evidence bringing new charges.

It was Thanksgiving 2012; 13-year-old budding athlete Dylan Redwine was visiting his dad Mark at his house in the San Juan Mountains of southwest Colorado.

It was a court-ordered visit: Dylan's mom and dad went through a contentious divorce. Mark says his son was sleeping when he went off to run some errands, and when he returned, Dylan was gone.

Hundreds of volunteers searched for the little boy. But Dylan was never found. His father appeared distraught.

Seven months later, a somber discovery: The melting snow reveals some of Dylan's remains about 10 miles north of his dad's house, off a twisting path deep in the woods. His devastated big brother Cory told our Denver affiliate KDVR he was in shock.

His mother Elaine was heartbroken. Mark's theory at the time? His son got lost and couldn't get cellphone reception. But Elaine wasn't buying it. She says she knows exactly what happened to Dylan and who killed him. She believes it's her ex-husband, Mark. Dylan's very own father.

Cops appeared to believe it too. Nearly three years after Dylan vanished they named Mark a "person of interest" and called the death "suspicious."

"We're pursuing this as a criminal investigation," said Dan Bender, a La Plata County Sheriff's spokesperson.

Mark has consistently denied any involvement. But cops hired former FBI Profiler Pete Klismet to study Mark Redwine's statements and media appearances. The result?

"The things Mark was saying didn't seem to mix well with everything else. I came to an inescapable conclusion: It had to be Mark," said Klismet.

Now five years after Dylan's disappearance, this case takes a major step forward. La Plata County investigators announce they finally have enough to indict Mark Redwine for the murder of his son, charging him with second-degree murder and child abuse knowingly or recklessly resulting in death.

Redwine is arrested Bellingham, Washington.

The stunning grand jury indictment finally details the years-long investigation. Dylan's blood was found in Mark Redwine's living room.

"Cadaver dogs indicated that a deceased person had been in his living room and bed of his pickup truck," the indictment reads. And a study of Dylan's skull revealing "blunt force trauma at two locations"... "consistent with tool marks from a knife."

But what on earth could drive a man to viciously murder his own 13-year-old son? After five years a bombshell secret emerges that cops believe turned the father into an alleged killer.

Investigators say Dylan saw compromising photos of his dad, and on that fateful Thanksgiving trip, planned to confront his father about them.

Dylan's brother Cory tells other media outlets that the pictures were "disgusting," allegedly depicting Mark Redwine in women's makeup, wearing a diaper, and other details too nauseating to repeat.

Being confronted with that was enough, investigators say, to throw Mark Redwine into a rage.

Now just this month, Mark Redwine makes his first pre-trial bond appearances.

Mark Redwine is currently locked up awaiting trial -- and after five years Dylan's mom Elaine can finally breathe a sigh of relief.