If the person responsible was someone who previously worked for the family, as the text and current reporting suggests, my question is how they knew OG would be at home. Police said she got home safely that night, so presumably the perpetrator was either 1) lying in wait or 2) got into the house at some point after she returned.
OG hadn't posted anything publicly about her specific plans for that weekend, although her husband did tweet about him and the oldest son being out of the area for a college tour, perhaps the perpetrator saw it and knew she and the young son would be home alone?