Was Being Scammed The Only Reason William Brock Murdered A Black Woman?

We're always left to speculate on these things.  I know none of my questions will be answered but I sure would like it if they were. 

William Brock was born in the 40's and went into his 20's in the 60's and as a white man, I can only imagine that he carried some influence from the time and place of his developmental years.  Some influence that could have played a role in his snap decision to murder a black person of whom is an unarmed woman walking away from him and clearly confused.