Produced by Liza Finley with Marcelena Spencer and Sara Rodriguez
(This story originally aired on Feb. 12)
WINTHROP, Wash. - It has been more than a year since celebrity dog trainer Mark Stover disappeared from his home in Anacortes, Wash.
"I love this area... I love everything about it, but it's different," Stover's sister, Vickie Simmons, says. "It's now the murder scene."
Police scoured the surrounding waterways.
"Mark Stover could be anywhere. He could be in a shallow grave. He could be in several pieces. We still don't know," says Private Investigator Leigh Hearon.
In the months before he died, Mark Stover feared someone was out to kill him. Terrified, he hired Private Investigator Leigh Hearon.
"He thought he was being followed...and that he was concerned for his own life," Hearon tells "48 Hours Mystery" correspondent Peter Van Sant. "It's almost as if he a premonition that he was going to die..."
And he told Leigh Hearon he thought he knew who wanted him dead: his ex-wife Linda Opdycke.
"I think Mark had a very real fear of what Linda was capable of doing to him," says Hearon.
The mystery had all the makings of a Hollywood movie. Linda Opdycke, the daughter of multimillionaire Wally Opdycke, drawn into the sensational murder investigation of her ex- husband; her boyfriend, Michiel Oakes, charged with the crime.
"Michiel would never murder anybody," Linda Opdycke tells Van Sant in an exclusive interview.
"And those who accuse him of doing just that?" he asks.
"They don't know him and they don't know the whole story," she replies.
No one believes in Michiel Oakes more than his four children. Amanda, 17, is his oldest daughter. "We are 100 percent sure he is not a murderer..." she says.
After getting a divorce from his first wife, Oakes took full custody of his four kids.
"...he'll sacrifice everything. His time, his money and like [laughs] everything just so we're happy and have a good life," says his 14-year-old daughter, April.
The son of a Boeing supervisor, Oakes grew up overseas. Smaller than most kids his age, he quickly learned how to stand up for himself, says his mom, Corrie. "He's a little warrior, but it's a gentle warrior..." she says.
That little warrior grew up to become a self-taught security specialist skilled in firearms.
"I ended up training with SWAT teams and so on and it's what we call force-on-force training," Oakes tells Van Sant.
Oakes' expertise in security eventually led him to Linda Opdycke, who told him her ex-husband, Mark Stover, was stalking her.
Mark Stover Voicemail: I'm a guy that can hold a grudge until I am dead!
"Michiel did an initial assessment for me and looked at the situation, my records and files, and saw what I was dealing with..." says Linda.
She confided in him the threats: "He told me that he would ruin my life," says Linda; Stover's menacing phone calls: "And I can hurt you too and I know how to do it;" and the fear.
Linda had turned her home into an armed fortress with more than 20 firearms and a video security system.
"I remember thinking this can't be real because no woman alone could go through this amount of harassment..." says Oakes.
Despite getting a protection order against Stover, the fear lingered and Oakes was there to protect Linda. They grew closer and fell in love.
"It's a beautiful love," Linda tells Van Sant. "...in my opinion it's legendary. It's something that you read about in romance novels or movies..."
Oakes and his children moved into Linda's home in Winthrop. It all seemed perfect.
"Mark, as far as I knew, was leaving me alone and he was going on his way, and I was going mine," says Linda.
What she didn't know, Oakes says, is that Mark Stover had set his sights on a new target.
"Mark Stover sought me out and told me that I would do what he wanted, "Oakes says."From that point for almost six months I lived in constant fear."
Oakes says his first terrifying encounter was in a Costco parking lot - when Mark Stover appeared out of nowhere.
"He said that he knew who I was and he knew that I was in a relationship with Linda... and he said there was something of his that she wouldn't give back and that I was going to get it for him..." says Oakes.
As bizarre as it sounds, Oakes says Stover demanded Linda's wedding photos and if he didn't get them, Oakes' children would pay the price.
"He went on to describe what my daughters were wearing that morning..." he says.
"And what did you realize at that moment?" asks Van Sant.
"That he had been following us the whole time... And he said you're going to get this, these wedding pictures back and they would be OK," Oakes says, getting emotional. "And I was very much afraid."
So afraid, Oakes trained his children how to defend themselves.
"...He started placing a firearm in my room," Amanda says, "and he told me if I thought I heard an intruder I was to take the handgun and fire at them."
Oakes says Stover's obsession with those wedding photos went on and on. He demanded secret meetings, including two at a church in Anacortes.
"Did Michiel tell you that Mark Stover approached him and told him information about the kids and demanded wedding photos?" Van Sant asks Linda Opdycke.
"No," she replies.
"Why wouldn't he share this vitally important information with you?" asks Van Sant.
"My guess, and knowing Michiel, is he really did not want to stress me out more..." she says, adding, "[Mark] was a deeply disturbed individual... He was a very disturbed person..."
Then Oakes says Stover demanded that he come to his home in Anacortes. Oakes says he had no choice; He had to go. "I was under tremendous pressure to do exactly what he wanted, exactly how he wanted it or suffer the consequences..."