PORTLAND, Oregon, July 4, 2010 -- One month after the disappearance of 7-year-old Kyron Horman, police reportedly said a landscaper told them the Oregon boy's stepmother tried to hire him to kill her husband, Kaine Horman.
The allegation, first reported in The Oregonian but confirmed by ABC News affiliate KATU-TV in Portland through a source close to the investigation, thickens the cloud of suspicion surrounding Terri Horman, the last person to see Kyron before he went missing on June 4.
Sources close to the investigation told the newspaper that police alerted Kaine Horman to the allegation on June 26, which they said is what prompted him to move out of the family home with his 19-month-old daughter and to file for divorce and a restraining order against his wife.
Two 911 calls were placed from the home of Kaine and Terri Horman that day. The first call was made in the evening lasted 13 minutes, the caller reporting threats of some kind. The second came in just after 11:30 p.m. and was written up only as a "child custody call."
The landscaper allegedly told police that Terri Horman approached him about killing her husband six or seven months before Kyron disappeared, the sources said.
Terri Horman denied the allegation when confronted by detectives, the newspaper reported, and she has not been charged, though the investigation is proceeding, the sources told The Oregonian.
Terri Horman hired prominent Portland criminal defense lawyer Stephen Houze early last week and was seen in his company as she returned home Wednesday night.
Kyron has been missing since June 4, but police say they have no reason not to believe he is still alive.
Multnomah County Sheriff Dan Staton said the investigation is not stalled, and they are still making progress.
"We have the potential to still bring him home," he said.
But it's an investigation that has so far failed to answer a heartbreaking question: What happened to Kyron Horman?
Terri Horman said she last saw him walking to his classroom after the two of them had attended a pre-school science fair together.
The school said he never made it to class, but he was not reported missing until the end of the day, when he did not get off the school bus that was supposed to bring him home.
Kyron's disappearance triggered the biggest search in Oregon history.
A week after Kyron vanished his family appeared together for the first time.
Kyron's stepfather, Tony Young, said, "Kyron, we miss you and love you and need you home."
It soon became a criminal case. On June 18, a police questionnaire asked if anyone saw Terri Horman the day he disappeared. She eventually took two lie detector tests, but police do not call her a suspect.
"We are not in a position to talk about suspects," Multnomah County Sheriff's Office Capt. Jason Gates said.
Kyron's biological mother, Desiree Horman, has insisted that her son "is still alive," but she also implied that Terri Horman knows more than she is telling.
"We implore Terri Horman to fully cooperate with the investigators to bring Kyron home," she said Thursday.
That is exactly what Terri Horman has been doing, though, Staton said on Friday.
"To date there has been no indication through our detectives or through our investigators that she's been uncooperative," Staton said at a news conference that was called because of the flood of media questions his office has received about the case.
Meanwhile, people have left cards and balloons at the fence outside Kyron's school, all expressing wishes for his safe return.
Police said they have chased nearly 3,000 leads, but the summer drags on ... without Kyron.