Literature question (or history)

In Toni Morrison’s book, “Song of Solomon”, she writes about a secret society called “The Seven Days” which is made up of black men that go around killing white people every time a black person is killed and justice is not done. Does anyone know if there is any historical accuracy to this, or did the author simply invent this group? Has anyone written anything about this topic that is available to read?

No, as far as I can tell it is fiction.

There was a “Battle of the Seven Days” in the Civil War, and that may be where Morrison got the name, but no historical references that I can locate.