I think her purse and cellphone are gonna be a bit of a problem for the defense. I don't have any young children now, but I always make sure I have my phone with me when I leave the house. You never know when you might have a flat tire, the car might not start if you're at an away-from-home location, one of the girls might have some sudden medial problem, DH might call, there could be an extended family emergency, or in SW's case, she might get a call having to do with Le-Vel/thrive. Also, why would she have left any of the going-out-for-a-while things at the house? If CW had said a prowler came in and murdered them, it would make much more sense to find those articles still at the home. And where do I put my phone when I'm going out? Duh, in my purse.
His alibi story is weak, weak, weak, IMO. He should have given it a bit more thought. It's gonna stick to him like tar.