OK... Here is one of my theories so far:
Motive: Kaine's Life Insurance, "substantial" Savings, Estate. Must take Kyron out of the picture before Kaine "dies," so that Kyron won't inherit the hefty child's portion. She didn't want to raise Kyron anyway--she secretly loathed him after K****, her REAL child, was born. She could just send him back to Desiree, but Desiree would gain control of Kyron's part of Kaine's estate, and Terri couldn't stand that thought.
Opportunity: Last big event day at school, chaotic, lots of people = plausible deniability. Terri had been planning this since the school year began. She had already started planning it by November 2009: a photo of Kyron on her facebook on K****'s November birthday has the caption "Kyron's class (Ms. Porter). Where was Kyron do you ask? Yeah, he went to the bathroom without telling anyone. *sigh*." And two weeks before the actual plan would be implemented, Terri told people at school that Kyron had been having "mini-seizures." I think that she had always planned for Kyron to die before Kaine--when she approached the landscaper about murder-for-hire, she was just getting her ducks in a row prior to taking out Kyron.
Theory: The morning of Kyron's science fair, Terri borrows Kaine's truck, using the excuse that she will be picking Kyron's project up after the science fair is over. (We know now that that project is retained by LE.)
Kaine leaves for work, and at 8:10, after Terri wraps up her FB games (last entry on FB was Family Feud at 8:01AM) and gets the things together that she'll need for the day, she loads K**** and Kyron into the truck.
At 8:30 Terri, Kyron, and K**** arrive at school. They go to Kyron's room, and Terri snaps the photo of him with his project. She also snaps a few other photos, like the one of Kyron's friend Ku***s' project, because she wants to look totally engaged in what's going on at Skyline.
While at the science fair, Terri tells Kyron's teacher that K**** isn't feeling well, and she also mentions that Kyron has a doctor's appointment for the mini-seizure thing. After all, it's noisy with so many kids and parents around, so Terri can get away with the doctor's appointment thing by later telling investigators, "But she must not have understood--I was talking about next Friday." Again, plausible deniability.
At 8:45, all students return to their classrooms. Kyron does not. Terri tells Kyron that she's taking him to the doctor, but they won't be there long, and he'll be back at school before lunch. At 8:45, all students and teachers are in their classrooms being divided up into groups and assigned an adult to tour with each group, so now is the perfect time to scram. Sometime between 8:45 and 9:00, Terri sends Kyron to the truck without her, because she can always say, "Oh, he forgot his ____ (lunchbox, pencil, whatever) in the truck," if someone sees him leave. After she's sure that Kyron's at the truck, Terri ducks out.
I think that Terri was trying to kill time from 9:00 until 10:00, to see if anyone from Skyline would notice Kyron missing. She couldn't act until 10:15, when she would be positive that roll had been taken as kids came back from their tour of the science fair. Kyron had to be kept alive from 9:00-10:15. Once 10:15 passed, she'd know that so far she was in the clear. While she was killing time between 9 and 10, Terri bought some benadryl at FM1, gave it to Kyron, and then drove a bit until it began to take effect. At FM2, Terri planned to spend more time inside, so she had to make sure that Kyron wouldn't get out of the truck and blow everything. (**see note)
**OK... here's where I can't figure it out. HOW was Terri able to go into two FMs between 9 and 10 without risking Kyron getting out of the truck and being seen. There are three possibilities: 1) Terri threatened Kyron within an inch of his life and told him to stay in the truck--and trusted that he would. Or 2) Someone else helped Terri and sat in the truck with Kyron, keeping him occupied. Or 3) He already knows that something is terribly wrong, as Terri has restrained him and has used plastic straps to secure his feet and hands to the front-seat brackets. He is lying on the floorboard behind the front seats, mouth duct taped, no way he can scream, covered by a blanket. Would Terri take such a chance, given that the school might call any moment to verify Kyron's absence? I think she would take such a chance... she knew that this would be her last opportunity until next school year. She took a risk, and was as nervous as a hooker in church from 9:00 til 10:15, hoping beyond hope that her earlier manipulations at the school had worked.
Back to the story: 10:15 arrives, and there's no call from Skyline, so Terri knows the plan can proceed. By now, Kyron is sedated, sleeping from the benadryl, so she drives to a secluded place, gets Kyron out of the truck, and then finally she does it. She kills Kyron. With her own daughter not ten feet from where her big brother is being murdered. Terri either strangles him or duct tapes his nose and mouth Casey-Anthony-style. She puts him in a garbage bag and then a duffel bag (or possibly a sterlite container like the ones on her back patio that is seen in numerous photos), to prevent any leakage in the truck. It's 10:45 now, so Terri calls Dede and tells her it's time to meet. She places the duffel bag or container in the bed of the pick-up. She takes a moment to calm herself...her adrenaline is pumping like mad through her veins.
At 10:45 after getting the call from Terri, Dede ducks away from her assigned task at Westwind, and she goes into the woods and stops in the edge of the woods where she has clear sight of the road, but where no one can see her. At 11:00, Dede sees Terri coming down the road, steps out, and gets in the truck with her.
Dede knows what she has to do, and she knows that time is very limited. Dede takes Terri to the gym, where Terri checks in at 11:39 and then puts K**** in daycare. Dede drives off to dispose of Kyron's body. She removes him from the canvas bag, and then from the garbage bag (or from the container). And dumps him. Or she buries him in the duffel bag or container. Where is unknown. But it's not in the Skyline area. It's south of Terri's gym, where no one would think to look.
At the gym, Terri goes to the shower first, takes a quick shower (but doesn't wash her hair), and puts on her workout clothes. She puts the clothes that she had worn that morning in an FM bag and puts it back into her gym bag. (There have been some suggestions that she may have had a duplicate set of clothing that she wore that morning, just in case LE asked her to turn over the clothes she was wearing. It's possible. In that case, she bags the clothes she had worn, disposes of them in a dumpster on the way home, and has the duplicate set of clothing ready to turn over, if LE should ask.) Terri does a quick work out at the gym, doesn't even break a sweat, and her batphone rings... it's Dede telling her it's done.
Dede leaves the dump site at 12:30 and heads back to pick up Terri and K****. Terri gets K**** from daycare and then signs out of the gym at 12:40. She gets in the truck with Dede. Terri drops Dede off at the woodline of Westwind, and Dede heads back through the woods to the site where she was working that morning.
Terri's home by 1:15 and on the computer. She uploads the photos of Kyron and the science fair at 1:21. Kaine arrives home at 2:00. He asks Terri why she didn't bring Kyron's science fair project home, and she tells Kaine that Kiara got sick at the science fair, so she had to leave to get Kiara some medicine, and then she drove around awhile to soothe her, and, well, you know how time gets away from ya. She assures him that she'll just pick it up Monday.
At 3:30, there's no Kyron on the bus, beginning the search for Kyron.
******************************************
I'm not completely committed to this theory. It's just one way to explain what few facts we know about what happened that day. Now go to work punching holes in it--I will NOT be offended.
