Investigators refuse to say whether they have a suspect.
Police passed out fliers Friday in hopes of jogging the memory of anybody who might have information on Kyron Horman's case, said Capt. Jason Gates of the Multnomah County Sheriff's Department.
The fliers show photos of the stepmother, Terri Moulton Horman, and the family's Ford F250 pickup.
A questionnaire that accompanies the flier has gone to everybody who was at Skyline School on June 4, he said. The boy was last seen there after a science fair he attended that morning with Terri Horman. Investigators say she told them she watched him walk toward his classroom before she left the school.
The stepmother, who has raised Kyron since he was an infant, contacted the school on the afternoon of the disappearance, when the boy didn't come home on his school bus. Kyron lived with his father and stepmother about 2 miles from the school.
The flier includes two questionnaires - a 10-question form directed at adults and an eight-question survey for children. Both ask if anyone saw Kyron or the stepmother at or near the elementary school, or if they witnessed a pickup truck matching the description of the family's Ford F250.
"The police going and putting flyers out with the stepmother's picture on it and her car speaks volumes that she is, absolutely, a person of interest," criminal profiler Pat Brown told "The Early Show on Saturday Morning" co-anchor Chris Wragge. As a matter of fact, I haven't seen this done hardly in any case before, so they are truly looking at her and wanting to know exactly -- something must have gone wrong. … They're also saying, by the way, it could be stranger-to stranger crime, but chances are very, very low. What does that say?"
Gates said he couldn't eliminate the possibility that Kyron was abducted by a stranger, but "the need for the public to be alarmed is very low."
The stepmother appeared at a news conference last week with the boy's father to appeal for help in finding the boy. "We fully support the release of this flier," said a family statement that Gates read Friday.
Searchers spent 10 days checking the area near the school and the family's home before the sheriff's office scaled back the search effort and reclassified the disappearance as a criminal investigation.
Searchers have been combing Sauvie Island, 10 miles northwest of downtown Portland, but police refuse to say why.
The Willamette Week newspaper, citing anonymous police sources, reported that cell phone records show Terri Horman was there June 4.
"I don't have control over what papers report," Gates said when asked about the Willamette Week article.
"There must be red flags up there somewhere," Brown observed. "Maybe the cell phone records aren't matching, her story isn't working. They must be really thinking this woman -- they either have to clear her, or they're gonna find out she was actually truly involved."
Terri Horman's Facebook activity has also been deemed suspicious by a bevy of armchair detectives - people leaving comments online - wondering why she was "hitting the gym" a few days after her stepson disappeared or why she failed to quickly change her profile picture from her biological daughter to Kyron.
"Everyone went, 'Wait a minute, you're going to the gym? Little boy's gone missing and you're going to the gym? How could you think of going to the gym?" ' Brown said. "I mean, that just really stunned everybody. And that's what started everything on Facebook, where people have started pointing fingers at the stepmother, thinking something's kind of wrong here."
The pickup was recently towed from the Horman home, but Gates said it was because of a mechanical problem, not the investigation.
Detectives have refused to answer most questions about the specifics of their investigation.
"Our primary goal is to not make any mistakes in this case, to be as perfect as we can be in investigating this case," Gates said.