It is pretty clear that the relationship was well and truly toxic by the time the police pulled the van over. My best bet is we will never know what transpired between the two on the afternoon of Gabby's murder. However, I suspect something happened that really triggered BL who appears to have been a very insecure guy. Controlling of GP's every move and every dollar spent. Keeping a watchful eye on any friendly interraction between GP and any potential romantic threat to himself, and insisting she make it very clear the two were engaged and she was off-limits. GP loved him and tried to patietly explain he had nothing to worry about as he eroded her sel-confidence, slowly dismantling her sense of self to prop himself up and keep her tied to team Petaundrie. However, GP fought back from time to time "sticking up for herself" - perhaps she yelled and got hysterical at time, perhaps she lashed out in the face of cruelty.
I feel BL truly believed he was the victim here - of a needy, borderline, Craaazy girl. Possible triggers IMO:
- financial dificulties (BL hated commercialism perhaps a perceived waste of money on a purchase)
- jealousy (GP was friendly to another male)
- residual embarassment over LE scene
- BL felt betrayed by GP who didn't support him during the restaurant fracas.
- GP emasculated BL and made him feel inadequate romantically
- GP told him that the relationship was over (a massive affront to his ego)
- In the course of an argument BL said the cruellest things and lashed out, scratching, biting or slapping BL which caused an immediate violent and lethal response.
Sadly, a scenario that plays out on any given Sunday all around the world. All the signs of co-ercive control were in that body-cam footage. Even foreshadowing of strangulation with hands on face. A little bit of GP died when LEC told her she was the party at fault, BL finished the job. MOO.