PORTLAND, Ore. - Desiree Young, the mother of missing boy, Kyron Horman, plans to file a civil suit against the boy's stepmother, Terri Horman.

The lawsuit, which sources tell KATU News will be filed on Friday, accuses Horman of "custodial interference."

Under Oregon law, custodial interference involves keeping a person from their legal custodian "permanently or for a protracted period."

Terri Horman was the last person known to have seen Kyron Horman before he disappeared from Skyline School almost exactly two years ago.

While Horman has never formally been named a criminal suspect, she has long been in the spotlight of the investigation.

It's not clear what evidence Young will lay out in her lawsuit.

It's also important to note that this civil suit is different from a criminal indictment and was not brought by prosecutors. There is a lower burden of proof to find someone guilty in a civil suit compared to a criminal trial.

In a criminal case a defendant must be found guilty "beyond a reasonable doubt." However, in a civil case a defendant must only be found guilty based on a "preponderance of evidence."

"I explain to people as if you have a scale and drop one grain of sand on the scale, that's all you have to show for preponderance of the evidence. So it's a very low standard," said family law attorney Drew Bobzien. Bobzien is not involved with the Young lawsuit.

Young and her attorneys are filing the lawsuit now because there is a two-year statute of limitations on bringing a suit. Kyron was reported missing on June 4, 2010.

Even with the lawsuit, we shouldn't expect to see Terri Horman take the stand and testify about the case. She'll be protected by the Fifth Amendment of the Constitution against incriminating herself because she could still face criminal charges in the case.

"There isn't really any reason to think that any kind of evidence would shake out of the tree," Bobzien said.

Anything Horman says in a civil case could ultimately be used against her in a potential criminal case.

A judge, however, could allow the civil trial to proceed without Horman's testimony, which would make it difficult for her to defend herself.

Law enforcement sources told KATU that members of the Kyron Horman task force met once again on Thursday morning to discuss the latest developments in the case.

Kaine Horman Reacts: 'The gloves are off'

In reaction to the expected civil lawsuit, Kyron's father, Kaine Horman, said standing next to the Wall of Hope, "I think at this point in time, the gloves are off."

He says by nature, he's a patient person. But his patience is worn thin when it comes to the unanswered questions about his son and what happened to him - answers he believes Terri Horman holds.

"This whole situation is about finding Kyron," he said. "There's no mistake about it whether we're going through a divorce or processing another part of the case that's involved with this or what have you, the discussions are always, what's the best approach to bring him home."

Kaine says he barely thinks about his estranged wife anymore but he thinks about Kyron every day.

The faded and worn items on the Wall of Hope signify the passing of time, the passing of seasons and all the stolen moments with his son he'll never get back.

But the idea that investigators haven't given up? That a lawsuit might somehow move the case forward?

"From my perspective is anything that we can do that's going to help reveal what's happened and get him home sooner, I'm all for it," Kaine said. "And if not doing something right now is the best approach or making a lot of noise by doing something right now is the best approach, by God we're going to do it."

KATU News checked back with deputies about the investigation Thursday. Chief Deputy Jason Gates has been on the case since the beginning and says he and his team are not going to give up.

"I'll never forget Kyron, and we are continuing to look for him," he said. "We are continuing this investigation. It's never been classified as a cold case. We've never stop investigating it. We've had a detective that is assigned to this case ever since. Our partner agencies, the DA's office is still actively involved with us of course."

A year ago a special task force to help find Kyron was dissolved but as Gates said the case is still active.

Since Kyron's disappearance investigators have received more than 5,000 tips, and they are still trickling in.

KATU News reporter Dan Tilkin contributed to this report.

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