The University of Missouri-St. Louis criminologist who's been one of the biggest skeptics of the "Ferguson Effect," which blames rising crime on the protests that followed Michael Brown's death at the hands of a police officer, is changing his tune.Rick Rosenfeld now says he believes there is a Ferguson Effect — something he had long doubted — but that it might not be as simple as originally postulated. In fact, he says there are two possible versions of the Ferguson Effect, and both offer intuitive explanations for why 56 U.S. cities are experiencing their worst homicide wave in decades.…