Actually, I think the perp in this case is the racist. Apparently, she was laughing to friends about running down a "white man". Her subsequent actions speak volumes about how she feels about white people.
He assumed that a white person wouldn't do something like this. That's rather silly considering all the Hannibal Lector comments. What about the Texas cases like the little girl in the closet or the mother drowning her children. The mother is on trial now so he can't say that he forgot about the case.