This is kind of funny. A novelist active in the 1890s was assumed by some twentieth century scholars to be black, on the basis of a photograph that might charitably be described as ambiguous and the fact her second novel took place in an area that later become a black tourist spot. That's it. No other evidence, and her novels apparently gave no indication that she might be black. Now she's been identified as white. But not before she'd inspired the reprinting of some old works by black women and the spilling of a fair amount of scholarly ink about her own novels' racial subtleties and whatnot.
Here's a link that provides links to the February 20th Boston Globe article that outed Kelley-Hawkins as white and articles commenting on the whole thing.