This is Crystal's take on this topic, from one of Nancy G's interviews:
How often, Crystal Sheffield, do you see her and why did she end up being with him?
CRYSTAL SHEFFIELD, MOM OF MISSING 5-YR-OLD HALEIGH CUMMINGS: I see them every two weeks. I pick them up on Friday at 6:00 and return them on Sunday at 6:00.
When me and Ronald split up I had the children with me, and I didn`t have the heart to keep them from him, and I let him come get them and he was supposed to return them to me and he never did, and then he went to the courthouse and filed for temporary custody, and the first court date was sent out to an address in Jacksonville, and it was a bogus address.
I never lived there, so I missed that court date, and then when we went for the custody hearing, they just -- I feel like they just blew me off, but they said they gave him custody because it was the best interest for the children.
GRACE: Are you saying the court blew you off?
SHEFFIELD: I just felt like they was all on his side.
http://transcripts.cnn.com/TRANSCRIPTS/0902/12/ng.01.html