The Multnomah County Sheriff's Office isn't commenting on the report, the paper says.
The Oregonian says the landscaper told investigators Terri Horman, stepmother of missing 7-year-old Kyron Horman, offered him lots of money six or seven months ago to kill Kaine Horman, Kyron's father.
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Detectives are said to have shared the story with Kaine, who then moved out with their 19 month old daughter, filed for divorce, and obtained a restraining order.
When questioned about the supposed scheme, Terri reportedly denied it.
If the landscaper's account is true, says CBS News legal analyst Lisa Bloom, "It tells the police that she may have a propensity for violence, violence against a close family member. So, it's certainly something they're going to follow up on."
"If it is true," criminal profiler Pat Brown told "Early Show" co-anchor Erica Hill Monday, "we're looking at a person who is -- wow, we're talking about a person with a severe personality disorder, psychopathy, someone who is willing to go to all kinds of lengths to get people out of her life, to get money or to get attention. We don't know which ones those are. But certainly, if that's true, they'll look at a person who very possibly could have done something to the stepson, because she already had the personality to do it."
In a briefing with reporters last week, Kyron's mother, Desiree Young, her voice cracking,, saying, "We implore Terri Horman to fully cooperate with the investigators to bring Kyron home."
Terri is the last person known to have seen the second-grader alive, at his school when he disappeared June 4. Police haven't named her a suspect or person of interest, and insist she's only one of many people still being eyed. She's hired a high-profile Portland attorney.
"Everyone's a person of interest," says Multnomah County Sheriff Dan Staton. "We have not named any suspects in this case at this point.
"Until Kyron is found," says Bloom, "I would not expect an arrest, unless there's a confession or a discovery of forensic evidence."
Brown observed to Hill that claiming nobody's off the hook in the case isn't unusual. "Police are always going on -- these days, there's always leaning on the side of being very careful about what they say," Brown noted. "I think everybody's afraid of lawsuits so they say everybody is a person of interest. However, they're also saying. 'We're not particularly worried about anybody in the community, there's no danger to anybody out there.' If that's true, then they're only looking at a family member. That's what they always say with they're looking at a situation that doesn't involve a predator.
"So, they're clearly looking at Terri Horman and, in my mind, she probably is the person of interest. But they're keeping options open, which they should, and they're not going to tell everybody exactly what they're thinking at the moment."