I kept thinking about those terms that were used; "actively strangling," wondering what benefit it could serve CW to say "actively," vs stumbling in on SW with the girls already dead.
And then I thought about what benefit it would serve CW to introduce the image of him viewing the active strangling through the baby monitor, vs. seeing it in person.
I can't help but wonder if he might have told LE during the confession that SW had locked the door, preventing him from helping his children. And that maybe he felt the need to say "actively" and "through the monitor" to support his claim that she was the one who killed the girls. Complete speculation, and I don't believe it would've been true for a second. Just thinking out loud on potentially filling that gap in the affidavit on what CW might have said to LE leading up to him "ultimately" strangling SW. Jmo