The way she spoke to her family! Like a Little Hitler - ordering them around and berating them. And it’s pretty clear they were on to her lies and worried that SHE was responsible for the kid’s disappearance. If this phone call doesn’t do her in, nothing will.
In their heart of hearts, they knew what their daughter was. If she talked like this to them while being filmed/recorded, you know it was worse when she knew noone could hear.