CW has confessed to killing SW and their unborn baby, he isn't innocent of that charge. So there's that.
CW had everything to gain by killing his family, total freedom and a big house to enjoy it in.
I understand some want physical proof on the bodies of Bella and CeCe that CW killed them. If it's found, will it make sense, of course, it won't. These family annihilations never make sense.
CW is being childish, such a quaint word for someone accused of despicable crimes but that's what's behind all this, he's scared, he's been caught out, he HAS to blame SW, it's too late to pin it on a random stranger, CW can't face the truth! Imo, the evidence will prove he's the killer of all 4 and SW's name will continue to shine.