This is a compelling story, but was told in the most inflammatory way. The 'Dad' does not seem credible at all. He contradicts himself depending on who he is trying to portray as the villain; Natalia or his ex-wife. He over-acts, fake cries and yells for no reason other than dramatic effect.
As for Natalia, she also seems a bit unreliable, but was still a victim of the people who should have taken care of her.
The experts that are interviewed have no first hand knowledge of the case, so it's basically just opinion masked as fact.
I wish it had been produced by actual documentarians that would have laid out a story chronologically that would have made a complete story.