In the United States jurors for grand juries are selected from jury pools. Court cases are decided by professional judges rather than juries. The modern criminal court jury arrangement has evolved out of the medieval juries in England. He called local jury commissioners to explain the absence of African-Americans from Jackson County juries. It also prohibits judges from overruling findings of fact by juries in federal civil trials. In effect they served as judges, juries, and executioners. There is no absolute prescription as to how judges should explain reasonable doubt to juries. Concerns were raised at the prospect of removing the requirement of juries within judicial trials. Most county grand juries in California do not consider criminal matters. Many states choose to use preliminary hearings instead of grand juries. Kentucky law prohibits convicted felons from serving on juries. Bean did not allow hung juries or appeals. Elected county councils took over the powers of the grand juries. The lack of juries in the District Court has been severely criticized. Two subsequent trials resulted in hung juries.