He vanished June 4 after attending a science fair at Skyline Elementary School, in the Portland area. It led to what was called at the time the biggest search in state history.
Over the weekend, reports correspondent Priya David Clemens, dozens of probers from several agencies scoured an area two miles from the school, in a massive ground search.
They were expected to return Monday.
Included in the search: property where Dede Spicher was working June 4. She is a close friend of Terri Horman, Kyron's stepmother, who's thought to be the last person to have seen him alive.
According to reports, it was a tip from Spicher that may have sparked this latest search, which follows Spicher's grand jury testimony, as well as that of other close friends of Terri Horman's. Kyron's parents and grade school principal also appeared in court last week. The grand jury is expected to hear from more witnesses this week.
Spicher is said to have helped Terri Horman buy an untraceable cell phone, and moved in with her for weeks.
"They're both presumed innocent," points out CBS News legal analyst Lisa Bloom . "Nevertheless, they both engaged in suspicious behavior that's making police look very closely at the both of them."
"It looks like Dede's opening up," attorney Bruce McCain, a former captain of the Multnomah County, Oregon Sheriff's Dept., told "Early Show" co-anchor Monday. " ... This is not a search-and-rescue. This is a forensic search for criminal evidence, more than likely, something very specific that Dede told them about. It could even very well be one of these untraceable cell phones."
Terri Horman hasn't been named a suspect in the case, but Kyron's parents believe she is involved in their son's disappearance.
Kyron's father, Kaine Horman, says he's living with the burden of guilt over having brought Terri into Kyron's life, saying, "It's my job to protect him ... and someone ... got him on my watch."
Saturday, hundreds of people gathered at Kyron's school, releasing balloons with messages of hope that the lost boy might soon be found.