PORTLAND -- The father of Kyron Horman warns the case for his missing young son may drag on for two, three or even four years.

And even then, the investigation into what happened to the missing boy may not be resolved.

During a two-hour interview with KGW, Kaine Horman provided insight into the nearly year-long investigation. If there is no major break in the case, this will be a marathon, not a sprint, according to Kaine Horman.

Kyron was last seen on June 4th, 2010. Through winter and early spring, search crews scoured an area near Skyline Boulevard in Northwest Portland. They found nothing. They also unsuccessfully searched areas on Sauvie Island.

Special coverage:Kyron Horman disappearance

Meanwhile, behind the scenes, Kaine said investigators were digging into his estranged wife's past.

During their time together, Kaine said, Terri Moulton-Horman lived a double life.

As investigators go through things, they found more stuff. That's really a lot of the questions. 'Hey, did you know about this? What about this?' A lot of it, I don't even know, I've never seen it before, said Kaine.

Police believe Terri was the last one to see her stepson at Skyline School. She has not been charged with any crimes and has since moved to Roseburg, where she lives with her parents.

When asked if he believes investigators have enough to convict his estranged wife for the disappearance of their son, Kaine Horman replied, I'll say 'no.' I think that there is still a significant amount of work that needs to be done to make sure that Terri is the right person.

Tuesday, go to kgw.com and watch KGW-TV at 11pm for part two of the interview with Kaine Horman.

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