I think it's pretty obvious they started out under the theory that Kyron wandered away from the school. Four days after he disappeared, Capt. Gates
said he hoped it would be "wrapped up by the end of the week". At that time he said there was no evidence of a crime. He also said that other children were not at risk, like they are saying now, but I think it may have been because at the time they thought Kyron was lost. Now they seem to be saying it for a very different, criminally related reason (that someone Kyron knows is responsible for his disappearance).
All of this says to me that LE got what they believe is very compelling evidence along the way which made them focus on TH. The search and rescue efforts were called off very abruptly, it was deemed a criminal investigation and they started searching the Sauvie Island area.
I am not sure they stopped searching abruptly. I know it was reported by some of the Sar people that areas were searched and re-searched so it may have just appeared abrupt. They did state they had a tip that led them to SI which is makes me feel that;
1. They thought he simply wandered off, no evidence of a crime
2. They searched for him for many days in the area of the school even after they had started looking at the island.
3. They received a tip that they took VERY seriously judging from the amount of effort put in to the search of the island and surrounding waters.
4. They have found no evidence of Kyron anywhere. Criminal or otherwise but have pretty much ruled out 'otherwise' so are left with criminal.
5. They refocused on Terri's story and asked for videos from businesses along certain paths she may have taken.
6. They questioned her and did poly's
7. It was easier to confirm alibi's for the other 3 parents because they were in specific places at specific times.
8. Terri was all over the place, checking her route and story is taking a lot more time and they can't/won't call her a POI because they have not discounted her story yet.
9. The poly's she took were inconclusive which really means squat because if she is taking any meds it will affect it anyway and they are pretty unreliable in the first place. We have someone here who has admitted that she 'failed' when asked her name and birth date. Terri is under tremendous stress right now.
10. LE can't clear Terri until they are through reviewing video.
11. Terri has tired of the speculation and with losing her husband and daughter, has hired an attorney possibly to clear her name because she is tired of waiting for LE to do it and wants her daughter back.