It could be that the shots heard by the neighbor were from the initial entry into the house. Father shot twice by the door from perp standing at the threshold of the door. This would account for "multiple shell casings" being reported before the report came in of the mom being found. Perp enters house, rounds up mom and Jayme. At that point a number of things could have happened. Finally call to 911 made, perp notices this, ends call and ,realizing he is out of time, shoots mom and leaves with Jayme. The shooting of the mom occurred deep in the house and was not heard by neighbor.