ROSEBURG — Ron Tarver hesitates when asked whether his ex-wife, Terri Moulton Horman, could be behind the disappearance of her stepson, Kyron Horman.

Tarver says she cheated on him during their four-year marriage. Then she left him in 1995. But responsible for what happened to a 7-year-old boy?

"I don't know [what she's capable of doing]," says Tarver, standing with his current wife, Angela Rockwood, outside their house in this Southern Oregon town of 21,000 people.

"We're not blind. Obviously they're zeroing in on Terri," Tarver says. "I just have a hard time believing anyone would be capable of doing that."

Tarver does know one thing for sure: Cops were homing in on Terri Moulton Horman within days of Kyron's disappearance. As first reported June 17 on, law-enforcement sources say the investigation has increasingly focused on Kyron's stepmom.

In the latest developments, Kyron's father, Kaine Horman, filed for divorce from Terri Moulton Horman on June 28, citing irreconcilable differences. He also took out a restraining order against her under the Family Abuse Prevention Act. A judge has sealed that request.

Tarver, who is 41, has followed the story from 200 miles away in Roseburg, tied to the unfolding drama by his marriage to Terri Moulton 19 years ago.

They were married in 1991, when Tarver was 22 and she was 21.

But the marriage fizzled, Tarver says, after Moulton began cheating on him and the restaurant they owned together failed.

Moulton kept custody of James, and Tarver saw the boy regularly on weekends—but recently, James left his mother's home to live with his maternal grandparents in Roseburg.

Until then James had been living with his mother and Kaine Horman off Cornelius Pass Road in unincorporated Multnomah County. Also sharing the house was Kyron, who is Kaine Horman's son from his first marriage, and Kiara, the couple's 18-month-old daughter.

After Kyron vanished, the reasons why James left his home and friends in Portland to move to Southern Oregon have been the subject of intense speculation. Terri Moulton Horman declined to comment when WW visited her home June 23.

James was a student at Lincoln High School in Portland, where he was on the swim team and played trumpet in the school band. Tarver says Terri Moulton Horman sent the boy to Roseburg in March this year because his grades were slipping and he was acting out at home.

"He and Kaine on occasion butted heads, because James is hard-headed," Tarver says.

Trouble hit home again when Kyron disappeared. The day after Kyron vanished, Tarver says, James went to the Hormans' house for a previously planned weeklong visit.

Tarver says on June 8, four days after Kyron disappeared, James called him from the Hormans' house and mentioned Terri Moulton Horman had taken a polygraph test. It's been reported that she has since taken a second polygraph. What hasn't been publicly confirmed until now is that authorities were already focusing on her so soon after Kyron vanished.

Tarver says when James mentioned the polygraph to him over the phone, he heard Terri Moulton Horman begin yelling in the background to be quiet and not reveal anything more. Given the intense media scrutiny, the family agreed James should return to Roseburg, Tarver says.

"It was a zoo, so we got him out of there," Tarver says. "It's just been devastating for the whole family. Obviously, the longer it drags on, the less chance there is for a happy ending."