I think we all agree on the fact that LE knows much more than they're saying.
Someone brought up the car seats a while ago...DS(Jr), IMO, didn't keep any car seats in his truck, on a PERMANENT basis, as MP most likely did. Even though it's an "extended cab", the space in the back seat area of his truck is small, and probably used for "other things" when he didn't have the kids. Been looking at the pics of his truck trying to see if anything was back there....no luck. Then again, maybe he DID have them there all the time, I'm just speculating that it's a good possibility, IMO, that he didn't.
Now....2 possibilities...either the routine was they transfered MP's seats from her auto to his....OR had another pair he put in each time he drove the kids to parents.
We don't know if it was a thing of just "handing off" the kids, or her going inside to help to do so.
With her going inside to get things situated, maybe put in video....kids kept busy...not pay attention...therefore, not hear anything.
DS, maybe says "come look what the kids made" or "what I did for the kids"....etc.
He has her alone, can easily overcome her....cover her mouth...strangle her.
NOW....why do I keep thinking "duffle bag"....the big greenish "military" ones. DS could say he's bringing something to the trash, or to grand parents house to the kids, still watching the video....at 3, maybe they could care less. Put it in the back of her Hummer. Use HER truck...child seats already there...we don't know if parents paid attention to WHICH car he was driving when dropping them off. Then said had to run an "errand"....like getting rid of poor MP.
I can, then, see him doing what seems to be running rampant in these crimes lately....drop off the Hummer in the parking lot....walk to a store thats somewhat close, but not too close....ask someone to pick him up....make excuse about using MP's Hummer and "running outta gas"...cough, cough...saying "that 'so and so' never does anything right, etc) and he'll get it later, etc.
We don't know if any friends came to LE with the call and "pick up"....AND, what ALWAYS gets me, is often LE/investigators/people never seem to think that, sometimes, people aren't watching out their windows....there ARE the times the suspect CAN get something so conspicuous as a large duffle bag into the back of the Hummer.
Also...maybe a lot of the people at the condo's work the 9 - 5 deal....not many witnesses then???
All just IMO and speculation.