Who is Officer Douglas in the novel, We Cast a Shadow?

Officer Douglas, a black man, is the notorious police officer who patrolled the Tiko community when the narrator was a child. In Chapter 12, the narrator remembers the man as a fearsome, omnipresent, and self-hating figure. Later in the novel, he is revealed to be the officer responsible for putting Sir in prison, after Sir reacted aggressively to him knocking Mama to the ground.