Despite specific and clear knowledge, Phoenix Police Chief Jeri Williams and other top department leaders failed for years to investigate a controversial challenge coin circulating among the ranks that celebrated officers shooting a protester in the groin with a pepper ball, according to an outside investigation obtained by ABC15.The investigation was completed by Ballard Spahr, a law firm hired to look into the matter after an ABC15 report exposed the coin’s existence and its ties to hate speech. The law firm also was hired to probe Phoenix’s role in charging protesters as a criminal street gang.