AB, EB and Zahra lived in a small 3 bedroom 1 bath home. In a home that small you are going to "run into" one of the other people that you live with even if you are home few hours of the day. AB also worked in lawn care, it is difficult for them to work in the dark so I have serious doubts about his working really long hours. From what I saw of the companies hours of operation I seem to recall that they are closed on Sundays.
AB knew that Zahra was not going to school since the move to Hickory. According to reports Zahra was being home schooled yet we have not heard of any home school books being found in the home. There was a sudden and drastic change in what Zahra was allowed to do once they moved into the Hickory home. Zahra was no longer allowed to play outside, go to friends houses or go to school. AB also never mentioned having a daughter to his neighbors at the Hickory home however he mentioned his dog. Neighbors have told LE and others that they had no idea that a child lived in the home as they never saw one there.
It was apparently common knowledge to neighbors (at their old addresses) and family that EB was abusing Zahra. It was said that the abuse even occured when AB was present and he did nothing to stop the abuse. Zahra had bruises visible to the school officials and in the last known photo of her. AB would have had to have been blind and deaf to not see and hear what was going on around him. AB did not remove Zahra from a situation where she was being abused, he did not call LE to report the abuse.
In all of the above Ab did nothing to protect his daughter. Even if AB did not physically hit, kill, dismember, cover-up, hide Zahra's body, etc he is still accountable for not protecting her and leaving her in a situation that led to her death. It is a parents responsibility to protect their child and if they refuse to do so and the child dies then that parent is as responsible as the person that committed the crime (IMO).