I would think that you have a legal right to know where your children are.
And I think you would be a dream client for any lawyer - it sounds like you're doing everything right.
I know you are missing out on your children, but once this is all behind you, you can catch up - and you will have the gift of realizing how precious they are to you. Had this not happened, your W might have continued the abuse you have described and you would have been too afraid to do anything - now you have an opportunity to stop it.
I think you have a baffled heart, and a loyal heart, that does not understand how someone can walk out like that.
M 16 yrs, WH62, P54 3 adult blended kids EA 11/13, BD1 6/14 PA fall 14, BD2 2/15 Piecing 2015, BD3 12/15 Separated 4/16 WH moved OW in 5/16 Divorced 6/15/17