I finally had a chance to watch this episode this weekend, but I had read bits and pieces in the news previously. According to her family, George was very controlling and abusive but would be very hot or cold, depending on the day. Shauna never knew how he was going to be and would feel like they could work things out when he was being nice, and then he would change on a dime the next time they spoke.
The Las Vegas news outlets reported that there was video surveillance of George making a duplicate key, which would explain the key that Greyhound used to gain entry into her home. For some reason, this wasn't mentioned in the 48 Hours episode. How would he have even known where she lived since she had only moved into this townhouse a few months earlier? The LV news also reported that there was a 3 minute phone call from George to Shauna around 9 p.m., while she was on her last work shift and immediately afterward, George called Greyhound, presumably to tell him what time she would be getting off work. It's not likely that Greyhound would have known that her shift ended at 3:00 a.m. any other way.
George's sisters were in such denial. What do they make of his driving 90 mph into a cement wall? What I find most disturbing is that George's mom has custody of the daughter. I don't understand why the courts would award custody to the parents of the mastermind/ killer when Shauna's sister might be a better option. So sad.