Kaine Horman, who was able to move back into the family's Portland home with the help of a judge's order, declined to say exactly why he believes a third party involved, but told The Oregonian in a statement that his opinion was "based upon briefings."
Terri Horman, the last person known to see 7-year-old Kryon alive, is living with her parents, 170 miles away from the home she once shared with the little boy, her husband and the couple's 20-month-old daughter. A judge ordered her out of the home over the weekend, just weeks after Kaine Horman fled with their little girl amid reports that Terri Horman allegedly approached the landscaper about killing him.
Kaine Horman also told The Oregonian that he changed the locks on the house's doors and fence.
Terri Horman has not been charged or named a person of interest in Kyron's disappearance or in the alleged murder-for-hire plot, but police and the second-grader's family are hoping the pressure she's now living with will cause her to crack.
"Catching criminals is a lot like catching fish," said criminal defense attorney John Hingson III, who is not involved with the Horman case. "What you need to do is to let the fish run and don't try to grab him before it's too early. The police are letting Terri Horman run."
Terri Horman and her attorney have declined to comment on the allegations made by Kyron's parents. Her lawyer, Stephen Houze, said that his client has been receiving death threats and that the media frenzy surrounding the case has morphed into a "witch hunt."
Bruce McCain, a retired captain with the Multnomah County Sheriff's Office, which is investigating Kryon's disappearance, said the case was at a crossroads and will remain that way until investigators can determine whether Kyron is dead or alive.
"Kyron is the absolute key," he told "Good Morning America." "Without Kyron's status known there probably won't be an arrest any time soon."
Kyron disappeared from his elementary school science fair on June 4. While Terri Horman was seen by her husband's side, presenting a united front with Kyron's biological mother and her husband, the family began to distance themselves from her within weeks.
Kyron's parents have publicly said they believe Terri Horman had something to do with the little boy's disappearance and his mother, Desiree Young, has pleaded with her more than once to tell police what she knows.
Kaine Horman, who was granted an emergency restraining order to keep his wife away from him and their daughter, filed for divorce last month, but it still wearing his wedding ring.
He told ABC's Portland affiliate KATU that even that decision was part of the plan to find Kyron.
"I think I keep it on as a symbol of our family and more for our kids than anything else," he told KATU. "It will come off at some point but right now the priority is getting Kyron home and taking care of Kiara."
McCain said Kaine Horman's public statements and accusations against his estranged wife are "very, very telling" with regards to what information the family and investigators have.