The one witness that spoke out claimed, the first thing she noticed was Gabby getting up crying. She thought they were kicked out. If this was the ongoing argument, it showed they were on very different paths. Brian looking at organic farms, Gabby pursuing an online influencer life. Very different lifestyles. And maybe it acuminated in the violence. Something happened. I dont think Brian woke up one day and said: "I think I'll kill the love of my life today."